Entacapone is a reversible inhibitor of peripheral catechol-O-methyltransferase (COMT) and is used as an adjunct to levodopa/carbidopa therapy in the treatment of Parkinson's disease. Clinically, COMT inhibitors improve levodopa availability in the CNS, thereby prolonging the motor response to levodopa treatment. Entacapone allows the patient's dosage of levodopa to be lowered, and results in a decrease in the incidence or severity of levodopa dose-related side effects (e.g., dyskinesia, nausea, etc.). With initial entacapone therapy, an increase in levodopa-induced side effects may be seen until the dosage of levodopa is adjusted downward. Entacapone treatment of Parkinson's disease patients has been associated with significant increases in daily "on" time and decreases in "off" time. In addition, entacapone has been shown to improve total activities of daily living and motor function scores, but it has no effect on cognitive function. Entacapone may be given with regular or controlled-release formulations of levodopa/carbidopa with or without the concurrent use of selegiline. As compared to another available COMT inhibitor, tolcapone, entacapone has a shorter duration of COMT inhibition but appears to have an improved side effect profile and does not require additional laboratory monitoring. The FDA approved entacapone in October 1999.
General Administration Information
For storage information, see specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
-May administer with or without food.
-Always administer with levodopa/carbidopa (either immediate or sustained release formulations).
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, the following centrally-mediated effects occurred in at least 1% of those receiving entacapone/levodopa and more frequently than in those receiving placebo/levodopa: dyskinesia (25% vs 15%), hyperkinesis (10% vs 5%), hypokinesia (9% vs 8%), dizziness (8% vs 6%), and drowsiness (2% vs 0%). Entacapone may potentiate the dopaminergic side effects of levodopa and may cause and/or exacerbate preexisting dyskinesia, especially during the first 8 weeks of therapy. Entacapone significantly increased the mean duration but not the magnitude of dyskinesia during clinical trials. The rates of discontinuation for dyskinesia were 1.5% and 0.8% for entacapone 200 mg and placebo, respectively. The overall incidence of dyskinesia declined during clinical trials in response to decreased dosages of levodopa and resolved in one-third of patients. Although decreasing the dose of levodopa may lessen levodopa dosage-induced side effects, patients may continue to experience frequent dyskinesias despite levodopa dosage reduction. Because entacapone may cause dizziness and drowsiness, patients should be advised to avoid driving, operating machinery, working at heights, or engaging in other tasks requiring mental alertness until they know how the drug affects them. Patients treated with entacapone have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living including the operation of motor vehicles, which sometimes resulted in accidents. Although many of these patients reported somnolence while on entacapone, some did not perceive warning signs, such as excessive drowsiness, and believed that they were alert immediately prior to the event. Some of these events have been reported as late as one year after initiation of treatment. It has been reported that falling asleep while engaged in activities of daily living always occurs in a setting of preexisting somnolence, although patients may not give such a history. Monitor patients for drowsiness or sleepiness because some of the events occur well after initiation of treatment with dopaminergic drugs. Patients may not acknowledge drowsiness or sleepiness until directly questioned about drowsiness or sleepiness during specific activities. Patients who have already experienced somnolence and/or an episode of sudden sleep onset should not participate in these activities during treatment with entacapone. Discontinue entacapone therapy in patients who develop significant daytime sleepiness or episodes of falling asleep during activities that require active participation (e.g., driving a motor vehicle, conversations, eating). If a decision is made to continue these patients on entacapone, advise them to avoid driving and other potentially dangerous activities. There is insufficient information to establish that dose reduction will eliminate episodes of falling asleep while engaged in activities of daily living.
Cases of severe rhabdomyolysis have been reported with entacapone use. It is not known what role entacapone had in these events, but rhabdomyolysis and associated myalgia has been associated with other drugs that increase dopaminergic activity. Severe prolonged motor activity including dyskinesia may account for the rhabdomyolysis; however, one case included fever and alteration of consciousness. Therefore, it is also possible that some cases of rhabdomyolysis may be the result of a reaction resembling neuroleptic malignant syndrome that has been reported in association with the rapid dose reduction or discontinuation of other dopaminergic drugs.
Post-marketing surveillance indicate that patients may experience new or worsening mental status and behavioral changes, which may be severe, including psychotic-like behavior during treatment or after initiating or increasing the dose of entacapone. Other drugs prescribed to improve the symptoms of Parkinson's disease can have similar effects on thinking and behavior. Abnormal thinking and behavior can cause psychosis, paranoid ideation, delusions, hallucinations, confusion, disorientation, aggressive behavior, agitation, and delirium. During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, the following psychiatric effects occurred in at least 1% of those receiving entacapone/levodopa and more frequently than in those receiving placebo/levodopa: anxiety (2% vs 1%) and agitation (1% vs 0%). Hallucinations developed in approximately 4% of patients treated with entacapone or placebo. Hallucinations have been associated with dopaminergic therapy such as levodopa, which was administered concomitantly with entacapone during clinical trials. Hallucinations led to treatment discontinuation (0.8% vs 0%) and hospitalizations (1% vs 0.3%) more frequently in those receiving entacapone than placebo. Patients may also develop symptoms of somnolence and decreased activity, states related to depressed level of consciousness (e.g., coma, confusion and disorientation), restlessness, agitation, and aggression, as well as discoloration of the tongue, skin, and the urine through overdose. During post-marketing surveillance, several cases of overdose have been reported; the highest reported overdose of entacapone was at least 40,000 mg.
Neuroleptic malignant syndrome-like symptoms characterized by elevated temperature (fever), muscular rigidity, altered consciousness, confusion, and elevated CPK levels have been reported in association with rapid dose reduction or withdrawal of other dopaminergic drugs. Abrupt discontinuation of entacapone should be avoided. When necessary, withdrawal of entacapone therapy should proceed slowly. In most of these cases, symptoms began after abrupt discontinuation of treatment with entacapone or reduction of its dose, or after the initiation of treatment with entacapone. It is not known what role entacapone had in these events. No cases have been reported following the abrupt withdrawal or dose reduction of entacapone treatment during clinical studies. Neuroleptic malignant syndrome should be considered in the differential diagnosis for any patient who develops a high fever or severe rigidity. Tapering entacapone has not been systematically evaluated. Rapid re-emergence of Parkinson's disease symptoms may occur on entacapone withdrawal, and concurrent dopaminergic therapies may need adjustment.
Dopaminergic therapy in Parkinson's Disease patients has been associated with orthostatic hypotension. Due to enhancement of the dopaminergic effects of levodopa, entacapone has been associated with orthostatic hypotension or syncope. During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, no differences from placebo were seen for measured orthostasis or symptoms of orthostasis. A total of 4.3% and 4% of patients treated with entacapone or placebo, respectively, reported orthostatic symptoms at some time during treatment and also had at least one unmeasured episode of orthostatic hypotension. At least one episode of syncope was reported in 1.2% and 0.8% of patients receiving entacapone or placebo, respectively. In controlled studies with entacapone, reports of syncope were generally more frequent in patients in both treatment groups who had an episode of documented hypotension. One case of ventricular tachycardia was noted in a healthy male volunteer after administration of an epinephrine infusion and oral entacapone. Because epinephrine is metabolized by catechol-o-methyltransferase (COMT), an interaction with entacapone appears probable.
Cases of retroperitoneal fibrosis, pulmonary infiltrates, pleural effusion, and pleural thickening have been reported in some patients treated with ergot derived dopaminergic agents (e.g., bromocriptine, pergolide). It is not known if non-ergot derived drugs such as entacapone have an association with these events. Four cases of pulmonary fibrosis were reported during clinical development of entacapone; three of these patients were also treated with pergolide and one with bromocriptine. The duration of treatment with entacapone ranged from 7-17 months.
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, the following gastrointestinal (GI) effects occurred in at least 1% of those receiving entacapone/levodopa and more frequently than in those receiving placebo/levodopa: nausea (14% vs 8%), diarrhea (10% vs 4%), dysgeusia (1% vs 0%), abdominal pain (8% vs 4%), constipation (6% vs 4%), vomiting (4% vs 1%), xerostomia (3% vs 0%), dyspepsia (2% vs 1%), flatulence (2% vs 0%), gastritis (1% vs 0%), and unspecified gastrointestinal disorders (1% vs 0%). Mild to severe diarrhea and colitis can occur during treatment with entacapone, and may be associated with weight loss, dehydration, and hypokalemia. During clinical trials, diarrhea was considered mild to moderate in 8.6% of patients and severe in 1.3% of patients. Treatment was discontinued in 1.2% of those with mild to moderate diarrhea and 0.5% of those with severe diarrhea, and 2 patients were hospitalized. During post-marketing use, drug-induced microscopic colitis, primarily lymphocytic colitis, has been reported. Symptoms of entacapone-induced colitis generally consist of moderate to severe, watery, non-bloody diarrhea which may be associated with dehydration, abdominal pain, weight loss, and hypokalemia. Diarrhea and colitis-related symptoms usually resolve or improve significantly upon discontinuation of the drug. Diarrhea commonly presents within 4-12 weeks of beginning entacapone treatment, but it may appear as early as the first week and as late as many months after the initiation of therapy. If prolonged diarrhea is thought to be related to entacapone treatment, the drug should be discontinued. If symptoms persist, diagnostic measures such as colonoscopy and biopsy should be considered.
Some patients receiving medications that increase dopaminergic tone, including entacapone, have reported intense and uncontrollable urges to gamble, increased sexual urges, intense urges to spend money uncontrollably, or other intense urges. Patients may be unable to control these urges while taking one or more of the medications that are used for the treatment of Parkinson's disease and that increase central dopaminergic tone, including entacapone taken with levodopa and carbidopa. Causality due to dopaminergic agents has not been established; however, in some cases, the urges stopped after the dose was reduced or the drug was discontinued. Practitioners should inquire periodically about new or worsening impulse control symptoms in patients receiving entacapone. Likewise, patients should be instructed to report such changes while receiving entacapone. Dose reduction or discontinuation should be considered in those who experience these effects.
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, hyperhidrosis occurred in 2% of those receiving entacapone/levodopa compared to 1% of those receiving placebo/levodopa.
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, the following respiratory effects or infections occurred in at least 1% of those receiving entacapone/levodopa and more frequently than in those receiving placebo/levodopa: dyspnea (3% vs 1%) and bacterial infection (1% vs 0%).
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, purpura occurred in 2% of those receiving entacapone/levodopa compared to 1% of those receiving placebo/levodopa.
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, urine discoloration occurred in 10% of those receiving entacapone/levodopa compared to 0% of those receiving placebo/levodopa. Patients should be advised that this change in color (a brownish orange discoloration) is not clinically relevant. In rat studies, there was an increased incidence of nephrotoxicity characterized by regenerative tubules, thickening of basement membranes, infiltration of mononuclear cells, and tubular protein casts. The significance of this finding in humans is unknown and there is no established method to monitor patients for this potential effect. Skin discoloration and tongue discoloration have been reported in association with entacapone overdose during post-marketing surveillance.
During clinical trials assessing entacapone as adjunct treatment to levodopa in Parkinson's disease, the following general effects occurred in at least 1% of those receiving entacapone/levodopa and more frequently than in those receiving placebo/levodopa: back pain (2-4% vs 1-2%), fatigue (6% vs 4%), and asthenia (2% vs 1%).
Entacapone is contraindicated in patients with a known hypersensitivity to entacapone or its ingredients.
Entacapone may potentiate the dopaminergic side effects of levodopa and may cause or exacerbate preexisting dyskinesia. Although decreasing the dose of levodopa may ameliorate this side effect, many patients in controlled studies continued to experience frequent dyskinesia despite a reduction in their dose of levodopa. The incidence of dyskinesia was 25% for treatment with entacapone and 15% for placebo. The incidence of study withdrawal for dyskinesia was 1.5% for 200 mg entacapone and 0.8% for placebo. Cases of severe rhabdomyolysis have been reported following the approval of entacapone. Although the reactions typically occurred while patients were treated with the drug, the complicated nature of these cases makes it difficult to determine what role, if any, entacapone played in their pathogenesis. Severe prolonged motor activity including dyskinesia may account for rhabdomyolysis. Signs and symptoms include fever, alteration of consciousness, myalgia, increased values of creatine phosphokinase (CPK) and myoglobin.
Avoid abrupt discontinuation of entacapone therapy when possible. Sporadic cases of a symptom complex resembling neuroleptic malignant syndrome (NMS) have been associated with dose reductions and withdrawal of entacapone or other medications with dopaminergic properties, and may be life-threatening. However, in some cases, hyperpyrexia and confusion were reported after initiation of treatment with entacapone. Hyperpyrexia and confusion are uncommon but they may be life-threatening with a variety of features, including hyperthermia/fever/hyperpyrexia, muscle rigidity, involuntary movements, altered consciousness/mental status changes, delirium, autonomic dysfunction, tachycardia, tachypnea, sweating, hypo- or hypertension, and abnormal laboratory findings (e.g., creatine phosphokinase (CPK) elevation, leukocytosis, myoglobinuria, and increased serum myoglobin). The early diagnosis of this condition is important for the appropriate management of these patients, which includes intensive medical monitoring and management. If a patient needs to discontinue or reduce their daily dose of entacapone, the dose should be decreased slowly, with supervision from a health care provider. Specific methods for tapering entacapone have not been systematically evaluated.
The administration of non-selective monoamine oxidase inhibitor therapy (MAOI therapy) is contraindicated with entacapone. Monoamine oxidase (MAO) and Catechol-O-Methyltransferase (COMT) are the 2 major enzyme systems involved in the metabolism of catecholamines. Concomitant use of non-selective MAOIs with entacapone may result in hypertensive crisis. Nonselective MAOIs are recommended to be discontinued at least 2 weeks prior to initiating therapy with entacapone. Selective MAO-B inhibitors and other standard drugs for Parkinson's disease may be used concomitantly with entacapone; however, dosage adjustments of therapies may be required. Drugs known to be metabolized by COMT should be administered with caution in patients receiving entacapone regardless of the route of administration (including inhalation), as interactions may result in increased heart rate, arrhythmia, and/or increased blood pressure.
Entacapone should be used cautiously in patients with hypotension or syncope. Dopaminergic therapy in Parkinson's disease patients has been associated with orthostatic hypotension. Entacapone enhances levodopa bioavailability and, therefore, may increase the occurrence of orthostatic hypotension or syncope. In controlled studies with entacapone, reports of syncope were generally more frequent in patients in both treatment groups who had an episode of documented hypotension. Advise patients that they may develop postural (orthostatic) hypotension with or without symptoms such as dizziness, nausea, syncope, and sometimes sweating. Advise patients to rise slowly, especially after long periods of sitting or lying down. Hypotension may be more likely when patients first start treatment. The FDA has reviewed extensive data for the cardiovascular safety of entacapone when used with levodopa; carbidopa, and there was no increased risk of heart attacks, stroke, or other cardiovascular events associated with the use of entacapone for the treatment of Parkinson's disease.
Patients should inform their surgeon and anesthesiologist of the use of entacapone prior to surgery, as COMT inhibitors may interact with some medications used in surgical procedures. If a patient requires general anesthesia for surgery, entacapone may be continued as long as the patient is permitted to take fluids and medication by mouth. Cases of neuroleptic malignant syndrome have been reported post-surgery so close monitoring is warranted; reinstitute entacapone therapy as soon as possible after the procedure.
Postmarketing reports indicate that patients may experience new or worsening mental status and behavioral changes, which may be severe, including psychotic-like behavior during entacapone treatment or after starting or increasing the dose of entacapone. Hallucinations have also been reported in patients receiving entacapone. In general, patients with a major psychotic disorder should not be treated with entacapone because of the risk of exacerbating psychosis. In addition, certain medications used to treat psychosis may exacerbate the symptoms of Parkinson's disease and may decrease the effectiveness of entacapone.
Entacapone has the potential to cause drowsiness or somnolence. Entacapone increases plasma levels of levodopa in patients taking concomitant carbidopa; levodopa products. Some Parkinson's disease patients taking dopaminergic medications, including entacapone, have reported sudden sleep onset while engaged in activities of daily living. Some of these episodes resulted in auto accidents or other harmful events. Although many of these patients reported somnolence while on entacapone, some did not perceive warning signs prior to these events, and some patients believed that they were alert immediately prior to the event. Some patients reported these events 1 year after the initiation of treatment. Patients should use extreme caution when driving or operating machinery or performing other tasks that require alertness while receiving entacapone. Reassessment for somnolence is necessary throughout therapy. Certain conditions may increase the risk of suddenly falling asleep and may include sleep disorders (e.g., narcolepsy, sleep apnea), ethanol ingestion, and coadministration with other CNS depressants or other interacting medications. Patients may not acknowledge drowsiness or sleepiness until directly questioned about somnolence during specific activities. Consider discontinuation of entacapone in patients that develop significant daytime sleepiness or episodes of falling asleep during activities that require active participation (e.g., conversations, eating, etc.). If a decision is made to continue the drug, patients should be advised to avoid driving or other potentially dangerous activities. There is insufficient information to establish if dose reduction will eliminate sudden episodes of falling asleep while engaged in activities of daily living.
Some patients receiving medications that increase dopaminergic tone have reported impulse control symptoms, including intense and uncontrollable urges to gamble, increased sexual urges, intense urges to spend money uncontrollably, or other intense urges. Patients may be unable to control these urges while taking one or more of the medications that are used for the treatment of Parkinson's disease and that increase central dopaminergic tone, including entacapone taken with levodopa and carbidopa. Causality due to dopaminergic agents has not been established; however, in some cases the urges stopped after the dose was reduced or the drug was discontinued. Because patients may not recognize these behaviors as abnormal it is important for practitioners to inquire periodically about new or worsening impulse control symptoms in patients receiving entacapone. Likewise, patients should be instructed to report such changes while receiving entacapone. Dose reduction or discontinuation should be considered in those who experience these effects.
Entacapone should be administered cautiously to patients with biliary obstruction, jaundice, or hepatic disease since biliary excretion appears to be the major route of excretion of entacapone and hepatic impairment increased entacapone exposure significantly in studies. All patients studied had biopsy-proven liver cirrhosis caused by alcohol; According to Child-Pugh grading, 7 of these patients had mild hepatic impairment and 3 patients had moderate hepatic impairment. Since entacapone is used with levodopa; carbidopa, periodic evaluation of hepatic function is recommended during extended therapy, as elevated hepatic enzymes may occur during combined treatment.
Cases of retroperitoneal fibrosis, pulmonary infiltrates, pleural effusion, and pleural thickening have been reported in some patients treated with ergot-derived dopaminergic agents. These complications may resolve when the drug is discontinued, but complete resolution does not always occur. Although these adverse reactions may be related to the ergoline structure of these compounds, a possible causal role of non-ergot drugs (e.g., entacapone), which increase dopaminergic activity, has also been considered. The expected incidence of fibrotic complications is so low that even if entacapone caused these complications at rates similar to those attributable to other dopaminergic therapies, it is unlikely that it would have been detected in a cohort of the size exposed to the drug during clinical trials prior to marketing. Four cases of pulmonary fibrosis have been reported during clinical development of entacapone; 3 of these patients were also treated with pergolide and 1 with bromocriptine. The duration of treatment with entacapone ranged from 7 months to 17 months.
Gastrointestinal (GI) symptoms may require evaluation and adjustment in therapy by the prescriber. Entacapone therapy commonly (10%) causes diarrhea. Typically, diarrhea presents within 4 to 12 weeks after entacapone is started, but it may appear as early as the first week and as late as many months after the initiation of treatment. Diarrhea may be associated with weight loss, dehydration, and hypokalemia, and in rare cases, has required hospitalization. Postmarketing experience has shown that diarrhea may be a sign of drug-induced microscopic colitis, primarily lymphocytic colitis. In cases of colitis, the diarrhea has usually been moderate to severe, watery and non-bloody, at times associated with dehydration, abdominal pain, weight loss, and hypokalemia. In the majority of cases, the symptoms resolved or significantly improved when entacapone was discontinued. In some patients with biopsy-confirmed colitis, diarrhea had resolved or significantly improved , but recurred after retreatment with entacapone. If prolonged diarrhea is suspected to be related to treatment, the drug should be discontinued and appropriate medical therapy considered. If the cause of prolonged diarrhea remains unclear or continues after stopping entacapone, then further diagnostic investigations including colonoscopy and biopsies should be considered.
Epidemiological studies have shown that patients with Parkinson's disease have a 2- to 6-fold higher risk of developing melanoma than the general population. It is unclear if this increased risk is disease-related or associated with other factors such as the medications used to treat Parkinson's disease. Therefore, it is recommended that a qualified practitioner (e.g., dermatologist) monitor for melanomas on a regular basis during entacapone use for any indication. In addition, patients should be instructed to regularly monitor for skin changes that may indicate the presence of melanoma and to promptly report these changes to their provider.
There is no experience from clinical studies regarding the use of entacapone during human pregnancy. The low molecular weight of the drug suggests that placental transfer is likely. Because human data are too limited to be conclusive and animal reproduction studies are not always predictive of human response, entacapone should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Entacapone is always given concomitantly with levodopa/carbidopa, which has been known to cause visceral and skeletal malformations in animals. During animal studies, when entacapone was given to rats prior to mating and during early gestation, an increased incidence of fetal eye anomalies was noted at high doses (plasma AUCs 7-times those in humans receiving the maximum daily dose). Entacapone has not shown to be teratogenic effects in rabbits. Entacapone did not result in impaired fertility or general reproductive performance in animals; however, delayed mating occurred at the highest dose. A case of neonatal seizure occurred after use of bromocriptine plus carbidopa/levodopa/entacapone in a pregnant woman. The effects of entacapone in labor and delivery are unknown.
According to the manufacturer, it is unknown if entacapone is excreted in human milk; however it is excreted into maternal milk in rats. The molecular weight of the drug suggests that excretion into human breast milk is likely. Because of the possibility that entacapone may be excreted into human milk, the manufacturer recommends caution when entacapone is administered to breast-feeding women. Since entacapone is always administered with carbidopa/levodopa, breast-feeding precautions for these agents should also be followed, as levodopa is excreted in human milk. If treatment with entacapone cannot be avoided during breast-feeding, the infant should be monitored for commonly encountered adverse effects of COMT inhibitor therapy including nausea, sedation, and diarrhea. One published study suggests that nursing or pumping milk at times of lower levodopa breast milk levels may help minimize the amount of levodopa received by an infant. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.
Safe and effective use of entacapone has not been established in pediatric patients. Juvenille Parkinson's disease is rare in children and adolescents. There is no identified potential use of entacapone in infants.
For the treatment of Parkinson's disease as an adjunct to carbidopa/levodopa for end-of-dose "wearing off":
Oral dosage:
Adults: 200 mg PO with each carbidopa/levodopa dose up to 8 times daily. Max: 1,600 mg/day. To optimize response, reductions in the daily levodopa dosage or extending the interval between levodopa dose may be necessary. Although tapering of entacapone has not been systemically evaluated, it is prudent to withdraw slowly to discontinue.
Maximum Dosage Limits:
-Adults
1,600 mg/day PO. Limited data are available for doses more than 1,600 mg/day.
-Geriatric
1,600 mg/day PO. Limited data are available for doses more than 1,600 mg/day.
-Adolescents
Safety and efficacy have not been established.
-Children
Safety and efficacy have not been established.
-Infants
Not indicated.
Patients with Hepatic Impairment Dosing
Use with caution in patients with hepatic impairment; carefully adjust dosage to clinical response. Specific dosage adjustment guidelines are not available.
Patients with Renal Impairment Dosing
No dosage adjustments are required; only 0.2% of a dose is excreted unchanged in the urine.
*non-FDA-approved indication
Acetaminophen; Aspirin; Diphenhydramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Caffeine; Dihydrocodeine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Acetaminophen; Caffeine; Pyrilamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Chlorpheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Codeine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Diphenhydramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acetaminophen; Hydrocodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Acetaminophen; Oxycodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Acrivastine; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Alfentanil: (Major) COMT inhibitors may cause additive sedation or hypotension with alfentanil. Monitor patients receiving alfentanil with other CNS depressants for hypotension and prolonged respiratory depression and sedation. In such cases of combined treatment, a dose reduction of one or both agents may be necessary.
Alprazolam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Amitriptyline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Amobarbital: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Amoxapine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as heterocyclic antidepressants, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Ampicillin: (Moderate) As entacapone is primarily excreted in the bile, caution should be exercised when drugs known to interfere with biliary excretion, glucuronidation, and intestinal beta-glucuronidation, such as ampicillin, are given concurrently with entacapone.
Ampicillin; Sulbactam: (Moderate) As entacapone is primarily excreted in the bile, caution should be exercised when drugs known to interfere with biliary excretion, glucuronidation, and intestinal beta-glucuronidation, such as ampicillin, are given concurrently with entacapone.
Aripiprazole: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Articaine; Epinephrine: (Moderate) Use COMT inhibitors and epinephrine, regardless of route, together with caution due to potential for increased heart rate, arrhythmias, and excessive changes in blood pressure. Epinephrine is metabolized by catechol-O-methyltransferase (COMT), therefore COMT inhibitors potentiate the pressor effects of epinephrine.
Asenapine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Aspirin, ASA; Butalbital; Caffeine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Aspirin, ASA; Carisoprodol; Codeine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Aspirin, ASA; Oxycodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Atropine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including systemic atropine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Atropine; Difenoxin: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including systemic atropine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
atypical antipsychotic: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Azelastine: (Moderate) An enhanced CNS depressant effect may occur when azelastine is combined with other CNS depressants including COMT inhibitors. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Azelastine; Fluticasone: (Moderate) An enhanced CNS depressant effect may occur when azelastine is combined with other CNS depressants including COMT inhibitors. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Baclofen: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Barbiturates: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Belladonna; Opium: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Benzhydrocodone; Acetaminophen: (Moderate) Concomitant use of opioid agonists with COMT inhibitors, such as entacapone, may cause additive sedation and somnolence. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Benzodiazepines: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Brexpiprazole: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Brompheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Brompheniramine; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Brompheniramine; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Bupivacaine; Epinephrine: (Moderate) Use COMT inhibitors and epinephrine, regardless of route, together with caution due to potential for increased heart rate, arrhythmias, and excessive changes in blood pressure. Epinephrine is metabolized by catechol-O-methyltransferase (COMT), therefore COMT inhibitors potentiate the pressor effects of epinephrine.
Buprenorphine: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Buprenorphine; Naloxone: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Butalbital; Acetaminophen: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Butalbital; Acetaminophen; Caffeine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known. (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Butalbital; Aspirin; Caffeine; Codeine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known. (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Butorphanol: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Calcium, Magnesium, Potassium, Sodium Oxybates: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sodium oxybate, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cannabidiol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cannabidiol and entacapone. CNS depressants can potentiate the effects of cannabidiol.
Capsaicin; Metaxalone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Carbinoxamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cariprazine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Carisoprodol: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Celecoxib; Tramadol: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Cenobamate: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and entacapone. Concurrent use may result in additive CNS depression. Dopaminergic agents, such as entacapone, have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Cetirizine: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cetirizine; Pseudoephedrine: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlophedianol; Dexbrompheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chloramphenicol: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation, or intestinal beta-glucuronidation such as chloramphenicol. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Chlorcyclizine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlordiazepoxide: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlordiazepoxide; Amitriptyline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them. (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlordiazepoxide; Clidinium: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Codeine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Dextromethorphan: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Hydrocodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpheniramine; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Chlorpromazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Chlorzoxazone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cholestyramine: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation, or intestinal beta-glucuronidation such as cholestyramine. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Clemastine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clobazam: (Moderate) An enhanced CNS depressant effect may occur when clobazam is combined with entacapone, a COMT inhibitor. Clobazam, a benzodiazepine, may cause drowsiness or other CNS effects. COMT inhibitors may cause drowsiness and have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clomipramine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clonazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clonidine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including clonidine, due to the possibility of additive sedation and hypotension. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clorazepate: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Clozapine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Codeine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Codeine; Guaifenesin: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Codeine; Guaifenesin; Pseudoephedrine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Codeine; Phenylephrine; Promethazine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Codeine; Promethazine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Cyclobenzaprine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cyproheptadine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dantrolene: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Desipramine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Deutetrabenazine: (Moderate) Concurrent use of deutetrabenazine and drugs that can cause CNS depression, such as entacapone, may have additive effects and worsen drowsiness or sedation. Advise patients about worsened somnolence and not to drive or perform other tasks requiring mental alertness until they know how deutetrabenazine affects them.
Dexbrompheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dexbrompheniramine; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dexchlorpheniramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dexmedetomidine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including dexmedetomidine, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Monitor patients closely for additive effects that may prolong recovery from dexmedetomidine administration.
Dexmethylphenidate: (Minor) Due to their pharmacologic actions, it is thought that increased dopaminergic effects may occur during coadministration of methylphenidate derivatives, inhibitors of dopamine reuptake, and COMT inhibitors. Be alert for any dopamine-related side effects such as nausea, reduced appetite, tremor, or changes in moods or behaviors.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Difelikefalin: (Moderate) Monitor for dizziness, somnolence, mental status changes, and gait disturbances if concomitant use of difelikefalin with CNS depressants is necessary. Concomitant use may increase the risk for these adverse reactions.
Dimenhydrinate: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diphenhydramine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diphenhydramine; Ibuprofen: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diphenhydramine; Naproxen: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diphenhydramine; Phenylephrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Diphenoxylate; Atropine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including systemic atropine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dobutamine: (Moderate) Drugs known to be metabolized by catechol-O-methyltransferase (COMT), such as dobutamine, should be administered cautiously to patients receiving COMT inhibitors. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Dopamine: (Moderate) Drugs known to be metabolized by catechol-O-methyltransferase (COMT), such as dopamine, should be administered cautiously to patients receiving COMT inhibitors. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Doxepin: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Doxylamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Doxylamine; Pyridoxine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Dronabinol: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including dronabinol, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Droperidol: (Major) Use droperidol with caution in patients taking COMT inhibitors due to the possibility of additive sedation. Droperidol produces marked tranquilization and sedation; reduced dosages may be needed in debilitated patients, particularly when combined with other CNS depressants.
Ephedrine: (Major) Drugs known to be metabolized by catechol-O-methyltransferase, such as ephedrine or ephedra, ma huang should be administered cautiously in patients receiving entacapone. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Ephedrine; Guaifenesin: (Major) Drugs known to be metabolized by catechol-O-methyltransferase, such as ephedrine or ephedra, ma huang should be administered cautiously in patients receiving entacapone. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Epinephrine: (Moderate) Use COMT inhibitors and epinephrine, regardless of route, together with caution due to potential for increased heart rate, arrhythmias, and excessive changes in blood pressure. Epinephrine is metabolized by catechol-O-methyltransferase (COMT), therefore COMT inhibitors potentiate the pressor effects of epinephrine.
Erythromycin: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as erythromycin. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Esketamine: (Major) Because of the possibility of additive sedative effects, caution is advisable during concurrent use of dopaminergic agents, such as entacapone, and CNS depressants, such as esketamine. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients who have received a dose of esketamine should be instructed not to drive or engage in other activities requiring complete mental alertness until the next day after a restful sleep.
Estazolam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Eszopiclone: (Major) A reduction in the dose of eszopiclone or concomitantly administered drugs with sedative properties (e.g., COMT inhibitors) should be considered to minimize additive sedative effects. In addition, the risk of next-day psychomotor impairment from eszopiclone may be increased during coadministration, which may decrease the ability to perform tasks requiring full mental alertness such as driving.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression.
Etomidate: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Fenfluramine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and entacapone. Concurrent use may result in additive CNS depression. Dopaminergic agents, such as entacapone, have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Fentanyl: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Flibanserin: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including flibanserin, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Fluphenazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Flurazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Food: (Major) Advise patients to avoid cannabis use while taking CNS depressants due to the risk for additive CNS depression and potential for other cognitive adverse reactions.
Gabapentin: (Major) Initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of gabapentin and entacapone. Concomitant use of gabapentin with entacapone may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression. Dopaminergic agents, such as entacapone, have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
General anesthetics: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Guanfacine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including guanfacine, due to the possibility of additive sedation or hypotension. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Haloperidol: (Major) Due to opposing effects on central dopaminergic activity, haloperidol and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an atypical antipsychotic as an alternative to haloperidol. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Heterocyclic antidepressants: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as heterocyclic antidepressants, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Homatropine; Hydrocodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Hydrocodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Hydrocodone; Ibuprofen: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Hydromorphone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Hydroxyzine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Ibuprofen; Oxycodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Iloperidone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Imipramine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Isocarboxazid: (Contraindicated) At least 14 days should elapse between the discontinuation of isocarboxazid, which is a non-selective MAO inhibitor, and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) are the 2 major enzymes involved in the metabolism of catecholamines. The combination of a COMT inhibitor and isocarboxazid may result in inhibition of the majority of pathways responsible for normal catecholamine metabolism, which may lead to hypertensive crisis or other adverse effects.
Isoflurane: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Isoniazid, INH: (Major) Patients should generally not receive COMT inhibitors in combination with agents that have some non-selective MAO inhibiting activity like isoniazid. It is recommended that at least 14 days should elapse between the discontinuation of a non-selective MAOI and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase and catechol-O-methyltransferase are the 2 major enzymes involved in the metabolism of catecholamines. It is possible that the combination of a COMT inhibitor and a non-selective MAOI would result in inhibition of the majority of pathways responsible for normal catecholamine metabolism.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Patients should generally not receive COMT inhibitors in combination with agents that have some non-selective MAO inhibiting activity like isoniazid. It is recommended that at least 14 days should elapse between the discontinuation of a non-selective MAOI and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase and catechol-O-methyltransferase are the 2 major enzymes involved in the metabolism of catecholamines. It is possible that the combination of a COMT inhibitor and a non-selective MAOI would result in inhibition of the majority of pathways responsible for normal catecholamine metabolism. (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as rifampin. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Isoniazid, INH; Rifampin: (Major) Patients should generally not receive COMT inhibitors in combination with agents that have some non-selective MAO inhibiting activity like isoniazid. It is recommended that at least 14 days should elapse between the discontinuation of a non-selective MAOI and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase and catechol-O-methyltransferase are the 2 major enzymes involved in the metabolism of catecholamines. It is possible that the combination of a COMT inhibitor and a non-selective MAOI would result in inhibition of the majority of pathways responsible for normal catecholamine metabolism. (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as rifampin. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Isoproterenol: (Moderate) Drugs known to be metabolized by catechol-O-methyltransferase, such as isoproterenol, should be administered cautiously in patients receiving COMT inhibitors. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Ketamine: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Lasmiditan: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lasmiditan and entacapone. Concurrent use may result in additive CNS depression. Dopaminergic agents, such as entacapone, have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Lemborexant: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and entacapone. Dosage adjustments of lemborexant and entacapone may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Levocetirizine: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Levorphanol: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Lidocaine; Epinephrine: (Moderate) Use COMT inhibitors and epinephrine, regardless of route, together with caution due to potential for increased heart rate, arrhythmias, and excessive changes in blood pressure. Epinephrine is metabolized by catechol-O-methyltransferase (COMT), therefore COMT inhibitors potentiate the pressor effects of epinephrine.
Linezolid: (Major) Avoid the concomitant use of COMT inhibitors in combination with linezoid, which has non-selective monoamine oxidase (MAO) inhibitor activity. Typically, at least 14 days should elapse between the discontinuation of a non-selective MAOI and the use of a COMT inhibitor to avoid potential interactions. Consider an alternative to linezolid if possible. Monoamine oxidase and catechol-O-methyltransferase (COMT) are the two major enzymes involved in the metabolism of catecholamines. It is theoretically possible that the coadministration of a COMT inhibitor with linezolid would result in inhibition of normal catecholamine metabolism and possible toxicity.
Lofexidine: (Major) Monitor for excessive hypotension and sedation during coadministration of lofexidine and entacapone. Lofexidine can potentiate the effects of CNS depressants.
Lorazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Loxapine: (Major) Due to opposing effects on central dopaminergic activity, loxapine and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider if an atypical antipsychotic is a potential alternative to loxapine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Lumateperone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Lurasidone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Maprotiline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as heterocyclic antidepressants, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Meclizine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Melatonin: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including melatonin, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Meperidine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Meprobamate: (Moderate) Additive CNS depressant effects are possible during coadministration of COMT inhibitors and meprobamate. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Metaxalone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Methadone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Methohexital: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Methyldopa: (Moderate) Drugs known to be metabolized by catechol-O-methyltransferase, such as methyldopa, should be administered cautiously in patients receiving COMT inhibitors. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure. Additive sedation and hypotension can occur. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Methylphenidate Derivatives: (Minor) Due to their pharmacologic actions, it is thought that increased dopaminergic effects may occur during coadministration of methylphenidate derivatives, inhibitors of dopamine reuptake, and COMT inhibitors. Be alert for any dopamine-related side effects such as nausea, reduced appetite, tremor, or changes in moods or behaviors.
Methylphenidate: (Minor) Due to their pharmacologic actions, it is thought that increased dopaminergic effects may occur during coadministration of methylphenidate derivatives, inhibitors of dopamine reuptake, and COMT inhibitors. Be alert for any dopamine-related side effects such as nausea, reduced appetite, tremor, or changes in moods or behaviors.
Metoclopramide: (Moderate) Coadministration of COMT inhibitors and metoclopramide should be avoided if possible. Metoclopramide may interfere with the effectiveness of COMT inhibitors. Metoclopramide has dopamine antagonist properties while COMT inhibitors increase the availability of catecholamine concentrations (e.g., dopamine) in the central nervous system.
Midazolam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Mirtazapine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as mirtazapine, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Molindone: (Major) Due to opposing effects on central dopaminergic activity, molindone and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an atypical antipsychotic. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Morphine: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Morphine; Naltrexone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Nabilone: (Moderate) Concomitant use of nabilone with other CNS depressants like entacapone can potentiate the effects of nabilone on respiratory depression.
Nalbuphine: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Nefazodone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as nefazodone, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Norepinephrine: (Moderate) Drugs known to be metabolized by catechol-O-methyltransferase, such as norepinephrine, should be administered cautiously to patients receiving COMT inhibitors. Concomitant use may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure.
Nortriptyline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Olanzapine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Olanzapine; Fluoxetine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Olanzapine; Samidorphan: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Oliceridine: (Major) Concomitant use of oliceridine with entacapone may cause excessive sedation and somnolence. Limit the use of oliceridine with entacapone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Opiate Agonists-Antagonists: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Orphenadrine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Oxazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Oxycodone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Oxymorphone: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Paliperidone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Pentazocine; Naloxone: (Major) Concomitant use of opiate agonists-antagonists with other central nervous system (CNS) depressants, such as COMT inhibitors, can potentiate the effects of the opiate agonists-antagonist and may lead to additive CNS or respiratory depression. Prior to concurrent use of a mixed opiate agonist-antagonist in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. If these agents are used together, reduced dosages may be necessary. Carefully monitor the patient for hypotension and CNS depression.
Pentobarbital: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Perampanel: (Moderate) Co-administration of perampanel with CNS depressants, including ethanol, may increase CNS depression. The combination of perampanel (particularly at high doses) with ethanol has led to decreased mental alertness and ability to perform complex tasks (such as driving), as well as increased levels of anger, confusion, and depression; similar reactions should be expected with concomitant use of other CNS depressants, such as entacapone.
Perphenazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Perphenazine; Amitriptyline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them. (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Phenelzine: (Contraindicated) At least 14 days should elapse between the discontinuation of phenelzine, which is a non-selective MAO inhibitor, and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) are the 2 major enzymes involved in the metabolism of catecholamines. The combination of a COMT inhibitor and phenelzine may result in inhibition of the majority of pathways responsible for normal catecholamine metabolism, which may lead to hypertensive crisis or other adverse effects.
Phenobarbital: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including scopolamine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including systemic atropine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Phenothiazines: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Pimozide: (Major) Due to opposing effects on central dopaminergic activity, pimozide and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an atypical antipsychotic instead of pimozide if appropriate. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Pramipexole: (Moderate) Coadministration of COMT inhibitors and pramipexole may cause additive sedation. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Pregabalin: (Major) Initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of pregabalin and COMT inhibitors. Concomitant use of pregabalin with COMT inhibitors may cause additive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Reassess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Prilocaine; Epinephrine: (Moderate) Use COMT inhibitors and epinephrine, regardless of route, together with caution due to potential for increased heart rate, arrhythmias, and excessive changes in blood pressure. Epinephrine is metabolized by catechol-O-methyltransferase (COMT), therefore COMT inhibitors potentiate the pressor effects of epinephrine.
Primidone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Probenecid: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as probenecid. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Probenecid; Colchicine: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as probenecid. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Procarbazine: (Major) Procarbazine has some non-selective MAO inhibiting activity. Typically, at least 14 days should elapse between the discontinuation of the non-selective MAOI and the use of a COMT inhibitor to avoid potential interactions. Patients should ordinarily not receive COMT-inhibitors in combination with agents with non-selective MAO inhibiting activity. MAO and COMT are the 2 major enzymes involved in the metabolism of catecholamines. It is theoretically possible that the combination of COMT-inhibitors and a non-selective MAOI would result in inhibition of the majority of pathways responsible for normal catecholamine metabolism.
Prochlorperazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Promethazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Promethazine; Dextromethorphan: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Promethazine; Phenylephrine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Propofol: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Protriptyline: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Pseudoephedrine; Triprolidine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Quazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Quetiapine: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Racepinephrine: (Major) Drugs known to be metabolized by catechol-O-methyltransferase (COMT), such as racepinephrine inhalations, should be administered cautiously in patients receiving COMT inhibitors like entacapone, tolcapone, or combinations containing these drugs such as carbidopa; levodopa; entacapone. If a patient is taking a COMT-inhibitor, then they should seek health care professional advice prior to the use of racepinephrine. Concomitant use may result in increased heart rate, possibly arrhythmias, and excessive changes in blood pressure. A single 400 mg dose of entacapone given with intravenous epinephrine has produced changes in heart rate and blood pressure. Ventricular tachycardia was noted in one healthy volunteer during an interaction study with epinephrine infusion and oral entacapone administration.
Ramelteon: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including ramelteon, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Remifentanil: (Major) COMT inhibitors may cause additive sedation or hypotension with remifentanil. Monitor patients receiving remifentanil with other CNS depressants for hypotension and prolonged respiratory depression and sedation. In such cases of combined treatment, a dose reduction of one or both agents may be necessary.
Remimazolam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Rifampin: (Moderate) Entacapone should be given cautiously with drugs known to interfere with biliary excretion, glucuronidation or intestinal beta-glucuronidation such as rifampin. Decreased biliary excretion of entacapone may occur if these agents are given concurrently.
Risperidone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Scopolamine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including scopolamine, due to the possibility of additive sedation. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Secobarbital: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as barbiturates, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should avoid driving or other hazardous tasks until the effects of the drug combination are known.
Sedating H1-blockers: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Serdexmethylphenidate; Dexmethylphenidate: (Minor) Due to their pharmacologic actions, it is thought that increased dopaminergic effects may occur during coadministration of methylphenidate derivatives, inhibitors of dopamine reuptake, and COMT inhibitors. Be alert for any dopamine-related side effects such as nausea, reduced appetite, tremor, or changes in moods or behaviors.
Sevoflurane: (Major) Additive CNS depression and hypotension may occur when general anesthetics and COMT inhibitors are used together. Monitor patients closely for additive effects that may prolong recovery.
Skeletal Muscle Relaxants: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Sodium Oxybate: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sodium oxybate, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Solriamfetol: (Moderate) Monitor for dopamine-mediated effects including nausea, vomiting, dizziness, tremor, and changes in moods or behaviors if solriamfetol, a central dopamine and norepinephrine reuptake inhibitor, is administered with other dopaminergic drugs, such as entacapone. Caution is recommended since this combination has not been evaluated.
Stiripentol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of stiripentol and entacapone. CNS depressants can potentiate the effects of stiripentol.
Sufentanil: (Major) COMT inhibitors may cause additive sedation or hypotension with sufentanil. Monitor patients receiving sufentanil with other CNS depressants for hypotension and prolonged respiratory depression and sedation. In such cases of combined treatment, a dose reduction of one or both agents may be necessary.
Suvorexant: (Moderate) CNS depressant drugs may have cumulative effects when administered concurrently and they should be used cautiously with suvorexant. A reduction in dose of the CNS depressant may be needed in some cases.
Tapentadol: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Tasimelteon: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tasimelteon, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Temazepam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Tetrabenazine: (Moderate) Concurrent use of tetrabenazine and drugs that can cause CNS depression, such as entacapone, may have additive effects and worsen drowsiness or sedation. Advise patients about worsened somnolence and not to drive or perform other tasks requiring mental alertness until they know how tetrabenazine affects them.
Thalidomide: (Major) The use of thalidomide and COMT inhibitors may cause an additive sedative effect and should be avoided if possible. If concurrent treatment is needed, prescribers should monitor patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Thioridazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Thiothixene: (Major) Due to opposing effects on central dopaminergic activity, thiothixene and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an atypical antipsychotic as an alternative to thiothixene. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Tizanidine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as tizanidine, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Tramadol: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Tramadol; Acetaminophen: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Tranylcypromine: (Contraindicated) At least 14 days should elapse between the discontinuation of tranylcypromine, which is a non-selective MAO inhibitor, and the use of a COMT inhibitor to avoid potential interactions. Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) are the 2 major enzymes involved in the metabolism of catecholamines. The combination of a COMT inhibitor and tranylcypromine may result in inhibition of the majority of pathways responsible for normal catecholamine metabolism, which may lead to hypertensive crisis or other adverse effects.
Trazodone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, such as trazodone, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Triazolam: (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Tricyclic antidepressants: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Trifluoperazine: (Major) Due to opposing effects on central dopaminergic activity, phenothiazines and COMT inhibitors may interfere with the effectiveness of each other. Avoid concurrent use if possible and consider an alternative to the phenothiazine. If coadministration cannot be avoided, monitor for changes in movement, moods, or behaviors.
Trimipramine: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Triprolidine: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including sedating H1-blockers, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Valerian, Valeriana officinalis: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including valerian, due to the possibility of additive sedation.
Valproic Acid, Divalproex Sodium: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including valproic acid, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Warfarin: (Moderate) Monitoring of the INR is recommended when entacapone treatment is initiated or when the dose is increased for patients receiving warfarin. Cases of significantly increased INR in patients concomitantly using warfarin have been reported during the postapproval use of entacapone. Entacapone has affinity for CYP2C9. In an interaction study in healthy volunteers, entacapone did not significantly change the plasma levels of S-warfarin while the AUC for R-warfarin increased on average by 18% (Cl 90 11% to 26%), and the INR values increased on average by 13% (Cl 90 6% to 19%).
Zaleplon: (Major) Additive CNS depressant effects are possible during concurrent use of COMT inhibitors and zaleplon. If concurrent use is necessary, monitor for additive side effects. A reduction in the dose of one or both drugs may be needed. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Ziprasidone: (Moderate) Monitor for movement disorders, unusual changes in moods or behavior, and diminished effectiveness of the atypical antipsychotic or COMT inhibitor during coadministration. Due to mutually opposing effects on dopamine, atypical antipsychotics and COMT inhibitors may interfere with the effectiveness of each other. In general, atypical antipsychotics are less likely to interfere with COMT inhibitors and other Parkinson's treatments than traditional antipsychotics. The Beers Criteria recognize quetiapine and clozapine as exceptions to the general recommendation to avoid all antipsychotics in older adults with Parkinson's disease.
Zolpidem: (Major) COMT inhibitors such as entacapone and tolcapone should be given cautiously with other agents that cause CNS depression, including zolpidem, due to the possibility of additive sedation. If concurrent use is necessary, monitor for additive side effects. A reduction in the dose of one or both drugs may be needed. For Intermezzo brand of sublingual zolpidem tablets, reduce the dose to 1.75 mg/night.
Zuranolone: (Major) Avoid the use of multiple sedating agents due to the risk for additive CNS depression. If use is necessary, consider a downward dosage adjustment of either or both medications, especially in patients with additional risk factors for sedation-related harm.
Entacapone is a reversible, selective inhibitor of peripheral catechol-O-methyltransferase (COMT). COMT acts to eliminate biologically active catechols and their metabolites. COMT catalyzes the transfer of the methyl group of S-adenyl-L-methionine to the phenolic group of substrates that contain a catechol structure. Substrates of COMT include dopa and catecholamines (dopamine, epinephrine, and norepinephrine) and their hydroxylated metabolites. COMT is distributed throughout various organs with the highest level of activity in the liver and kidney. Other organs that contain COMT are the heart, lung, smooth and skeletal muscle, intestinal tract, reproductive organs, adipose tissue, various glands, skin, blood cells, and neuronal tissues, especially glial cells. Following 200 mg of entacapone, erythrocyte COMT activity is inhibited roughly 65% and returns to baseline within 8 hours. In the presence of a decarboxylase inhibitor (e.g., carbidopa), COMT becomes the major metabolizing enzyme for levodopa, which results in formation of a levodopa metabolite (3-O-methyldopa) that has been associated with reduced efficacy of levodopa, the 'wearing-off' phenomenon, and dyskinesia. Entacapone should always be administered in association with levodopa and carbidopa. Entacapone has no antiparkinsonian effect of its own. Inhibition of COMT by entacapone and inhibition of decarboxylase by carbidopa results in more sustained plasma concentrations of levodopa and markedly lower 3-O-methyldopa concentrations. As a result, more levodopa is available for diffusion into the CNS where it is converted to dopamine, thereby potentiating the activity of dopamine in the CNS. When entacapone is given with levodopa and carbidopa, the AUC of levodopa is increased by approximately 35% and the elimination half-life of levodopa is increased from 1.3 hours to 2.4 hours. In general, levodopa peak plasma levels and time to peak plasma levels are unaffected. The higher AUC and duration of action may lead to increased levodopa adverse effects, sometimes requiring a reduction in the levodopa dosage.
Entacapone is administered orally and exhibits linear pharmacokinetics that are independent of levodopa/carbidopa coadministration. It is 98% protein bound to albumin primarily and, therefore, is not widely distributed into tissues. Metabolism is extensive and occurs through isomerization to the cis-isomer, followed by direct glucuronidation of both the parent and cis-isomer. The glucuronide metabolites are inactive. Only a very small amount (0.2% of the dose) is found unchanged in the urine. After oral administration, 10% of the dose is excreted in the urine and 90% in the feces via biliary excretion. The elimination half-life is 1 to 2 hours following a 200 mg dose, which is similar to the half-life of levodopa.
Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: COMT, CYP2C9
Entacapone is a selective and reversible inhibitor of catechol-O-methyltransferase (COMT) and may influence the pharmacokinetics of drugs metabolized by COMT. Entacapone has also been reported to increase the exposure of warfarin (a CYP2C9 substrate). In vitro studies have shown that entacapone can inhibit CYP1A2, CYP2A6, CYP2C6, CYP2C19, CYP2D6, CYP2E1 and CYP3A4, but only at very high concentrations (IC50 more than 200 microM) that would not be seen with normal clinical use. A 200 mg dose in adults usually produces a concentration of 5 microM.
-Route-Specific Pharmacokinetics
Oral Route
Entacapone is rapidly absorbed after oral administration with an absolute bioavailability of 35%. The mean peak concentration (Cmax) of 1160 to 1500 mcg/L is attained approximately 1 hour following a 200 mg dose. Food does not affect the pharmacokinetics of entacapone.
-Special Populations
Hepatic Impairment
Following a single 200 mg dose of entacapone (without levodopa/carbidopa coadministration), patients with hepatic impairment had approximately 2-fold higher AUC and Cmax values than normal patients. Multiple dose studies are not available. As only about 10% of the entacapone dose is excreted in urine as parent compound and conjugated glucuronide, biliary excretion appears to be the major route of excretion. Dosage adjustment may be necessary in patients with hepatic impairment or biliary obstruction.
Renal Impairment
Only 0.2% of an entacapone dose is excreted unchanged in the urine, and only 10% of the total dose appears in the urine, as inactive metabolites and unchanged drug. No important effects of renal function on the pharmacokinetics of entacapone were found in a specific renal impairment study. There were 3 groups: normal subjects (n = 7); patients with moderate renal impairment (n = 10; creatinine clearance ranging from 0.60 to 0.89 mL/second/1.73 m2), and severe impairment (n = 7; CrCl 0.20 mL to 0.44 mL/second/1.73 m2).
Geriatric
Entacapone pharmacokinetics are independent of age.
Gender Differences
No formal gender studies have been conducted.
Ethnic Differences
Racial representation in entacapone clinical studies was largely limited to Caucasians; therefore, no conclusions can be reached about the effect of the drug on groups other than Caucasian.