Flavoxate is an oral urinary antispasmodic agent. It is used for the symptomatic relief of dysuria, urgency, nocturia, suprapubic pain, and the frequency and incontinence associated with other genitourinary disorders (e.g., cystitis, prostatitis, urethritis). Flavoxate is not indicated as definitive treatment for genitourinary disorders but is used with other drugs indicated for treating urinary tract infections. This drug was approved by the FDA in 1970.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
-Flavoxate may be administered on an empty stomach with water. If gastric irritation occurs, take with food or milk.
Adverse reactions to flavoxate are usually a result of its pharmacological actions. Gastrointestinal adverse reactions that have been reported include nausea, vomiting, and xerostomia.
CNS adverse reactions reported with flavoxate use include vertigo, headache, mental confusion (especially in the elderly), drowsiness, and nervousness.
There was one case of leukopenia reported in association with flavoxate use, which was reversible upon drug discontinuation.
Cardiovascular adverse reactions reported with flavoxate use include sinus tachycardia and palpitations.
Reported adverse allergic reactions to flavoxate include urticaria and other dermatoses, eosinophilia, and hyperpyexia.
Adverse ophthalmic reactions reported with flavoxate use include increased ocular tension, blurred vision, and disturbance in accommodation.
Dysuria has been reported during the use of flavoxate.
The anticholinergic effects of flavoxate may be significant and are additive with other anticholinergic medications. Flavoxate has a direct spasmolytic effect on smooth muscle of the GI tract and bladder. The drug is contraindicated in patients with GI obstruction (pyloric or duodenal obstruction, obstructive intestinal lesions, ileus, or achalasia), GI bleeding, urinary retention, or lower urinary tract obstruction (i.e., bladder obstruction due to prostatic hypertrophy or urethral stricture).
Flavoxate should be used with caution in patients with closed-angle glaucoma. Flavoxate has been associated with increased ocular tension, increased intraocular pressure, and other ocular disturbances.
The safe and effective use of flavoxate in neonates, infants and children less than 12 years of age has not been determined.
Use flavoxate with caution in the geriatric adult, due to the anticholinergic effects of the drug. According to the Beers Criteria, antimuscarinics with strong anticholinergic properties, such as flavoxate, are considered potentially inappropriate medications (PIMs) in geriatric adults with dementia/cognitive impairment (adverse CNS effects) or delirium/high risk of delirium (new-onset or worsening delirium).
According to the manufacturer, it is not known whether flavoxate is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when flavoxate is administered to breast-feeding women. The effects of flavoxate are similar to other anticholinergics; one potential effect of anticholinergic drugs is the reduction of milk production, particularly when lactation is being established. In addition, the nursing infant may be more susceptible to anticholinergic effects, similar to other pediatric populations. 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 administered drug, healthcare providers are encouraged to report the adverse effect to the FDA.
Flavoxate is classified in FDA pregnancy risk category B. There are no adequate and well-controlled studies in pregnant women. No adverse effects were noted in animal reproduction studies (at doses up to 34 times the human dose). However, because animal reproduction studies are not always predictive of human response, flavoxate should be used during pregnancy only if clearly needed.
Patients should be advised to use caution when driving or operating machinery while receiving flavoxate. This drug can cause drowsiness, vertigo, blurred vision, and other ocular disturbances.
The weak anticholinergic activity of flavoxate can suppress sweat gland activity causing increases in body temperature. Flavoxate should be prescribed cautiously for patients who experience conditions which contribute to an elevation in core body temperature, such as strenuous exercise, ambient temperature increase, or dehydration.
Flavoxate used for prolonged periods or in large doses may decrease or inhibit salivary flow. This can contribute to the development of dental caries, periodontal disease, oral candidiasis, and oral discomfort. Use with caution in patients with significant dental disease.
Anticholinergics, such as flavoxate, may exacerbate the clinical symptoms of patients with myasthenia gravis or autonomic neuropathy.
For the symptomatic relief of dysuria, urinary urgency, nocturia, suprapubic pain, urinary frequency, and urinary incontinence associated with cystitis, overactive bladder (OAB)*, prostatitis, urethritis, urethrocystitis, or urethrotrigonitis:
Oral dosage:
Adults, Adolescents, and Children >= 12 years: 100-200 mg PO 3-4 times per day, adjusted according to response and tolerance.
Maximum Dosage Limits:
-Adults
No specific maximum dosage information is available.
-Elderly
No specific maximum dosage information is available.
-Adolescents
No specific maximum dosage information is available.
-Children
>= 12 years: No specific maximum dosage information is available.
< 12 years: Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustments in hepatic impairment are not available; the routes of metabolism of flavoxate are not known.
Patients with Renal Impairment Dosing
Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.
*non-FDA-approved indication
AbobotulinumtoxinA: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Acetaminophen; Aspirin; Diphenhydramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when dihydrocodeine is used concomitantly with an anticholinergic drug. The concomitant use of dihydrocodeine and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Acetaminophen; Caffeine; Pyrilamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Chlorpheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Diphenhydramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetaminophen; Hydrocodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Oxycodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant oxycodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Acetylcholine Chloride: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Aclidinium: (Moderate) Although aclidinium is minimally absorbed into the systemic circulation after inhalation, there is the potential for aclidinium to have additive anticholinergic effects when administered with other anticholinergics or antimuscarinics. Per the manufacturer, avoid concomitant administration of aclidinium with other anticholinergic medications, when possible.
Aclidinium; Formoterol: (Moderate) Although aclidinium is minimally absorbed into the systemic circulation after inhalation, there is the potential for aclidinium to have additive anticholinergic effects when administered with other anticholinergics or antimuscarinics. Per the manufacturer, avoid concomitant administration of aclidinium with other anticholinergic medications, when possible.
Acrivastine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Alfentanil: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when alfentanil is used concomitantly with an anticholinergic drug. The concomitant use of alfentanil and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Aliskiren; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Alosetron: (Major) Concomitant use of alosetron and anticholinergics, which can decrease GI motility, may seriously worsen constipation, leading to events such as GI obstuction, impaction, or paralytic ileus. Although specific recommendations are not available from the manufacturer, it would be prudent to avoid anticholinergics in patients taking alosetron.
Aluminum Hydroxide: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Aluminum Hydroxide; Magnesium Carbonate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Aluminum Hydroxide; Magnesium Hydroxide: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Aluminum Hydroxide; Magnesium Hydroxide; Simethicone: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Aluminum Hydroxide; Magnesium Trisilicate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Amantadine: (Moderate) Medications with significant anticholinergic activity may potentiate the anticholinergic effects of amantadine, and may increase the risk of antimuscarinic-related side effects.
Amiloride; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Amitriptyline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Amoxapine: (Moderate) Depending on the specific agent, additive anticholinergic effects may be seen when amoxapine is used concomitantly with other anticholinergic agents. Clinicians should note that anticholinergic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive CNS effects are also possible when these drugs are combined with amoxapine.
Antacids: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) Additive anticholinergic effects may be seen when orphenadrine is used concomitantly with other antimuscarinics.
Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Aspirin, ASA; Oxycodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant oxycodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Atenolol; Chlorthalidone: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Atropine; Difenoxin: (Moderate) Diphenoxylate is a synthetic opiate derivative that appears to exert its effect locally and centrally on the smooth mucle cells of the GI tract to inhibit GI motility and slow excess GI propulsion. The effects can be additive to antimuscarinic agents, such as flavoxate. In some cases, constipation might occur, and effects on the CNS or bladder function may also be additive.
Azilsartan; Chlorthalidone: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Belladonna; Opium: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when opium is used concomitantly with an anticholinergic drug. The concomitant use of opium and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Benazepril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Benzhydrocodone; Acetaminophen: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when benzhydrocodone is used concomitantly with an anticholinergic drug. The concomitant use of benzhydrocodone and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Bethanechol: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Bisoprolol; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Botulinum Toxins: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Brompheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Brompheniramine; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Brompheniramine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Buprenorphine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant buprenorphine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Buprenorphine; Naloxone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant buprenorphine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Bupropion: (Moderate) Bupropion exhibits moderate anticholinergic effects. Clinicians should keep this in mind when using antimuscarinics and other medications with anticholinergic activity in combination with bupropion.
Bupropion; Naltrexone: (Moderate) Bupropion exhibits moderate anticholinergic effects. Clinicians should keep this in mind when using antimuscarinics and other medications with anticholinergic activity in combination with bupropion.
Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Butalbital; Aspirin; Caffeine; Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Butorphanol: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when butorphanol is used concomitantly with an anticholinergic drug. The concomitant use of butorphanol and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Calcium Carbonate: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Calcium Carbonate; Famotidine; Magnesium Hydroxide: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Calcium Carbonate; Magnesium Hydroxide: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Calcium Carbonate; Magnesium Hydroxide; Simethicone: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Calcium Carbonate; Simethicone: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Calcium; Vitamin D: (Major) Avoid concomitant use of calcium carbonate and anticholinergics. Antacids may interfere with the absorption of anticholinergics.
Candesartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Captopril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Carbinoxamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Celecoxib; Tramadol: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant tramadol and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Cetirizine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Cetirizine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Cevimeline: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Chlophedianol; Dexbrompheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorcyclizine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlordiazepoxide; Amitriptyline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorothiazide: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Chlorpheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Dextromethorphan: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Hydrocodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpheniramine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Chlorpromazine: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including chlorpromazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Chlorthalidone: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Cholinergic agonists: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Cisapride: (Moderate) Because flavoxate can inhibit the motility of the GI tract via anticholinergic actions, it has the potential to interfere with the action of drugs that stimulate GI motility, such as cisapride.
Clemastine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Clomipramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Clozapine: (Major) Avoid co-prescribing clozapine with other anticholinergic medicines that can cause gastrointestinal hypomotility, due to a potential to increase serious constipation, ileus, and other potentially serious bowel conditions that may result in hospitalization. Clozapine exhibits potent anticholinergic effects. Additive anticholinergic effects may be seen when clozapine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the anticholinergic agent used.
Codeine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Guaifenesin: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Phenylephrine; Promethazine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant promethazine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Codeine; Promethazine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant promethazine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Crofelemer: (Moderate) Pharmacodynamic interactions between crofelemer and antimuscarinics are theoretically possible. Crofelemer does not affect GI motility mechanisms, but does have antidiarrheal effects. Patients taking medications that decrease GI motility, such as antimuscarinics, may be at greater risk for serious complications from crofelemer, such as constipation with chronic use. Use caution and monitor GI symptoms during coadministration.
Cyclobenzaprine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cyclobenzaprine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Cyproheptadine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dasiglucagon: (Major) The concomitant use of intravenous glucagon and anticholinergics increases the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. Concomitant use is not recommended.
DaxibotulinumtoxinA: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Desipramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dexbrompheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dexbrompheniramine; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dexchlorpheniramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dextromethorphan; Bupropion: (Moderate) Bupropion exhibits moderate anticholinergic effects. Clinicians should keep this in mind when using antimuscarinics and other medications with anticholinergic activity in combination with bupropion.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dextromethorphan; Quinidine: (Moderate) The anticholinergic effects of quinidine may be significant and may be enhanced when combined with antimuscarinics.
Digoxin: (Moderate) Anticholinergics, because of their ability to cause tachycardia, can antagonize the beneficial actions of digoxin in atrial fibrillation/flutter. Routine therapeutic monitoring should be continued when an antimuscarinic agent is prescribed with digoxin until the effects of combined use are known.
Dimenhydrinate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenhydramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenhydramine; Ibuprofen: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenhydramine; Naproxen: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenhydramine; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenoxylate; Atropine: (Moderate) Diphenoxylate is a synthetic opiate derivative that appears to exert its effect locally and centrally on the smooth mucle cells of the GI tract to inhibit GI motility and slow excess GI propulsion. The effects can be additive to antimuscarinic agents, such as flavoxate. In some cases, constipation might occur, and effects on the CNS or bladder function may also be additive.
Disopyramide: (Moderate) In addition to its electrophysiologic effects, disopyramide exhibits clinically significant anticholinergic properties. These can be additive with other anticholinergics. Clinicians should be aware that urinary retention, particularly in males, and aggravation of glaucoma are realistic possibilities of using disopyramide with other anticholinergic agents.
Donepezil: (Moderate) The therapeutic benefits of donepezil, a cholinesterase inhibitor, may be diminished during chronic co-administration with antimuscarinics or medications with potent anticholinergic activity. When concurrent use is not avoidable, the patient should be monitored for cognitive decline and anticholinergic side effects. Clinicians should generally avoid multiple medications with anticholinergic activity in the patient with dementia. Some of the common selective antimuscarinic drugs for bladder problems, (such as oxybutynin, darifenacin, trospium, fesoterodine, tolerodine, or solifenacin), do not routinely cause problems with medications used for dementia, but may cause anticholinergic side effects in some patients. Atropine may be used to offset bradycardia in cholinesterase inhibitor overdose.
Donepezil; Memantine: (Moderate) The adverse effects of anticholinergics, such as dry mouth, urinary hesitancy or blurred vision may be enhanced with use of memantine; dosage adjustments of the anticholinergic drug may be required when memantine is coadministered. In addition, preliminary evidence indicates that chronic anticholinergic use in patients with Alzheimer's Disease may possibly have an adverse effect on cognitive function. Therefore, the effectiveness of drugs used in the treatment of Alzheimer's such as memantine, may be adversely affected by chronic antimuscarinic therapy. (Moderate) The therapeutic benefits of donepezil, a cholinesterase inhibitor, may be diminished during chronic co-administration with antimuscarinics or medications with potent anticholinergic activity. When concurrent use is not avoidable, the patient should be monitored for cognitive decline and anticholinergic side effects. Clinicians should generally avoid multiple medications with anticholinergic activity in the patient with dementia. Some of the common selective antimuscarinic drugs for bladder problems, (such as oxybutynin, darifenacin, trospium, fesoterodine, tolerodine, or solifenacin), do not routinely cause problems with medications used for dementia, but may cause anticholinergic side effects in some patients. Atropine may be used to offset bradycardia in cholinesterase inhibitor overdose.
Doxepin: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Doxylamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Doxylamine; Pyridoxine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Dronabinol: (Moderate) Use caution if coadministration of dronabinol with anticholinergics is necessary. Concurrent use of dronabinol, THC with anticholinergics may result in additive drowsiness, hypertension, tachycardia, and possibly cardiotoxicity.
Eluxadoline: (Major) Avoid use of eluxadoline with medications that may cause constipation, such as anticholinergics. Discontinue use of eluxadoline in patients who develop severe constipation lasting more than 4 days.
Enalapril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Eprosartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Fentanyl: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant fentanyl and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Fluphenazine: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including fluphenazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Fluticasone; Umeclidinium; Vilanterol: (Moderate) There is the potential for umeclidinium to have additive anticholinergic effects when administered with other anticholinergics or antimuscarinics. Per the manufaturer, avoid concomitant administration of umeclidinium with other anticholinergic medications when possible.
Fosinopril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Galantamine: (Moderate) The therapeutic benefits of galantamine, a cholinesterase inhibitor, may be diminished during chronic co-administration with antimuscarinics or medications with potent anticholinergic activity. When concurrent use is not avoidable, the patient should be monitored for cognitive decline and anticholinergic side effects. Clinicians should generally avoid multiple medications with anticholinergic activity in the patient with dementia. Some of the common selective antimuscarinic drugs for bladder problems, (such as oxybutynin, darifenacin, trospium, fesoterodine, tolerodine, or solifenacin), do not routinely cause problems with medications used for dementia, but may cause anticholinergic side effects in some patients. Atropine may be used to offset bradycardia in cholinesterase inhibitor overdose.
Glucagon: (Major) The concomitant use of intravenous glucagon and anticholinergics increases the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. Concomitant use is not recommended.
Glycopyrronium: (Moderate) Although glycopyrronium is minimally absorbed into the systemic circulation after topical application, there is the potential for glycopyrronium to have additive anticholinergic effects when administered with other antimuscarinics. Per the manufaturer, avoid concomitant administration of glycopyrronium with other anticholinergic medications.
Guaifenesin; Hydrocodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Guanidine: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Homatropine; Hydrocodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Hydrochlorothiazide, HCTZ; Moexipril: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Hydrocodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydrocodone; Ibuprofen: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydrocodone; Pseudoephedrine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant hydrocodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydromorphone: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when hydromorphone is used concomitantly with an anticholinergic drug. The concomitant use of hydromorphone and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Hydroxyzine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Ibritumomab Tiuxetan: (Moderate) Use anticholinergics, such as flavoxate, and concomitant solid oral dosage forms of potassium chloride with caution due to risk for gastrointestinal mucosal injury. Anticholinergics may decrease gastric motility and increase the transit time of solid oral dosage forms of potassium chloride leading to prolonged contact with the gastrointestinal mucosa.
Ibuprofen; Oxycodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant oxycodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Imipramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
IncobotulinumtoxinA: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Ipratropium: (Moderate) Although ipratropium is minimally absorbed into the systemic circulation after inhalation, there is the potential for additive anticholinergic effects when administered with other antimuscarinic or anticholinergic medications. Per the manufacturer, avoid coadministration.
Ipratropium; Albuterol: (Moderate) Although ipratropium is minimally absorbed into the systemic circulation after inhalation, there is the potential for additive anticholinergic effects when administered with other antimuscarinic or anticholinergic medications. Per the manufacturer, avoid coadministration.
Irbesartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Itraconazole: (Moderate) Antimuscarinics can raise intragastric pH. This effect may decrease the oral bioavailability of itraconazole; antimuscarinics should be used cautiously in patients receiving itraconazole.
Levocetirizine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Levorphanol: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when levorphanol is used concomitantly with an anticholinergic drug. The concomitant use of levorphanol and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Linaclotide: (Moderate) Anticholinergics can promote constipation and pharmacodynamically oppose the action of drugs used for the treatment of constipation or constipation-associated irritable bowel syndrome, such as linaclotide.
Lisinopril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Losartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Loxapine: (Moderate) Loxapine has anticholinergic activity. The concomitant use of loxapine and other anticholinergic drugs can increase the risk of anticholinergic adverse reactions including exacerbation of glaucoma, constipation, and urinary retention. Depending on the agent used, additive drowsiness/dizziness may also occur.
Lubiprostone: (Moderate) Antimuscarinic drugs can promote constipation and pharmacodynamically oppose the action of drugs used for the treatment of constipation, such as lubiprostone. The clinical significance of these potential interactions is uncertain.
Lurasidone: (Moderate) Antipsychotic agents may disrupt core temperature regulation; therefore, caution is recommended during concurrent use of lurasidone and medications with anticholinergic activity such as antimuscarinics. Concurrent use of lurasidone and medications with anticholinergic activity may contribute to heat-related disorders. Monitor patients for heat intolerance, decreased sweating, or increased body temperature if lurasidone is used with antimuscarinics.
Macimorelin: (Major) Avoid use of macimorelin with drugs that may blunt the growth hormone response to macimorelin, such as antimuscarinic anticholinergic agents. Healthcare providers are advised to discontinue anticholinergics at least 1 week before administering macimorelin. Use of these medications together may impact the accuracy of the macimorelin growth hormone test.
Magnesium Hydroxide: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Maprotiline: (Moderate) Additive anticholinergic and CNS effects may be seen when maprotiline is used concomitantly with flavoxate.
Meclizine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Memantine: (Moderate) The adverse effects of anticholinergics, such as dry mouth, urinary hesitancy or blurred vision may be enhanced with use of memantine; dosage adjustments of the anticholinergic drug may be required when memantine is coadministered. In addition, preliminary evidence indicates that chronic anticholinergic use in patients with Alzheimer's Disease may possibly have an adverse effect on cognitive function. Therefore, the effectiveness of drugs used in the treatment of Alzheimer's such as memantine, may be adversely affected by chronic antimuscarinic therapy.
Meperidine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when meperidine is used concomitantly with an anticholinergic drug. The concomitant use of meperidine and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Methadone: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when methadone is used concomitantly with an anticholinergic drug. The concomitant use of methadone and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Metoclopramide: (Moderate) Drugs with significant antimuscarinic activity, such as anticholinergics and antimuscarinics, may slow GI motility and thus may reduce the prokinetic actions of metoclopramide. Monitor patients for an increase in gastrointestinal complaints, such as reflux or constipation. Additive drowsiness may occur as well. The clinical significance is uncertain.
Metolazone: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Metoprolol; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Molindone: (Moderate) Antipsychotics are associated with anticholinergic effects; therefore, additive effects may be seen during concurrent use of molindone and other drugs having anticholinergic activity such as antimuscarinics. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other CNS effects may also occur.
Morphine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant morphine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Morphine; Naltrexone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant morphine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Nabilone: (Moderate) Concurrent use of nabilone with anticholinergics may result in pronounced tachycardia and drowsiness.
Nalbuphine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when nalbuphine is used concomitantly with an anticholinergic drug. The concomitant use of nalbuphine and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Nortriptyline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Olanzapine: (Moderate) Additive anticholinergic effects may be seen when olanzapine and anticholinergics are used concomitantly; use with caution. Use of olanzapine and other drugs with anticholinergic activity can increase the risk for severe gastrointestinal adverse reactions related to hypomotility. Olanzapine exhibits anticholinergic activity. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the anticholinergic agent used.
Olanzapine; Fluoxetine: (Moderate) Additive anticholinergic effects may be seen when olanzapine and anticholinergics are used concomitantly; use with caution. Use of olanzapine and other drugs with anticholinergic activity can increase the risk for severe gastrointestinal adverse reactions related to hypomotility. Olanzapine exhibits anticholinergic activity. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the anticholinergic agent used.
Olanzapine; Samidorphan: (Moderate) Additive anticholinergic effects may be seen when olanzapine and anticholinergics are used concomitantly; use with caution. Use of olanzapine and other drugs with anticholinergic activity can increase the risk for severe gastrointestinal adverse reactions related to hypomotility. Olanzapine exhibits anticholinergic activity. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the anticholinergic agent used.
Oliceridine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when oliceridine is used with flavoxate. Use of anticholinergics may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Olmesartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
OnabotulinumtoxinA: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Orphenadrine: (Moderate) Additive anticholinergic effects may be seen when orphenadrine is used concomitantly with other antimuscarinics.
Oxycodone: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant oxycodone and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Oxymorphone: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when oxymorphone is used concomitantly with an anticholinergic drug. The concomitant use of oxymorphone and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Paroxetine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant anticholinergic medication and paroxetine use. Concomitant use may result in additive anticholinergic adverse effects.
Pentazocine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when pentazocine is used concomitantly with an anticholinergic drug. The concomitant use of pentazocine and anticholinergic medications may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Pentazocine; Naloxone: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when pentazocine is used concomitantly with an anticholinergic drug. The concomitant use of pentazocine and anticholinergic medications may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Perphenazine: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including perphenazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Perphenazine; Amitriptyline: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including perphenazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Phentermine; Topiramate: (Moderate) Monitor for decreased sweating and increased body temperature, especially in hot weather, during concomitant use of topiramate and other drugs that predispose persons to heat-related disorders, such as anticholinergic medications. Concomitant use increases the risk for oligohidrosis and hyperthermia.
Pilocarpine: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Potassium Bicarbonate: (Moderate) Use anticholinergics, such as flavoxate, and concomitant solid oral dosage forms of potassium chloride with caution due to risk for gastrointestinal mucosal injury. Anticholinergics may decrease gastric motility and increase the transit time of solid oral dosage forms of potassium chloride leading to prolonged contact with the gastrointestinal mucosa.
Potassium Chloride: (Moderate) Use anticholinergics, such as flavoxate, and concomitant solid oral dosage forms of potassium chloride with caution due to risk for gastrointestinal mucosal injury. Anticholinergics may decrease gastric motility and increase the transit time of solid oral dosage forms of potassium chloride leading to prolonged contact with the gastrointestinal mucosa.
Pralidoxime: (Major) The muscarinic actions of drugs known as parasympathomimetics, including both direct cholinergic receptor agonists and cholinesterase inhibitors, can antagonize the antimuscarinic actions of anticholinergic drugs, and vice versa.
Pramlintide: (Major) Pramlintide therapy should not be considered in patients taking medications that alter gastric motility, such as anticholinergics. Pramlintide slows gastric emptying and the rate of nutrient delivery to the small intestine. Medications that have depressive effects on GI could potentiate the actions of pramlintide.
Procainamide: (Moderate) The anticholinergic effects of procainamide may be significant and may be enhanced when combined with anticholinergics. Anticholinergic agents administered concurrently with procainamide may produce additive antivagal effects on AV nodal conduction, although this is not as well documented for procainamide as for quinidine.
Prochlorperazine: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including prochlorperazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Promethazine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant promethazine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Promethazine; Dextromethorphan: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant promethazine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Promethazine; Phenylephrine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant promethazine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Protriptyline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Pseudoephedrine; Triprolidine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Quetiapine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant quetiapine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Quinapril; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Quinidine: (Moderate) The anticholinergic effects of quinidine may be significant and may be enhanced when combined with antimuscarinics.
Rasagiline: (Moderate) MAOIs exhibit secondary anticholinergic actions. Additive anticholinergic effects may be seen when MAOIs are used concomitantly with antimuscarinics. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive CNS effects are also possible when many of these drugs are combined with MAOIs.
Remifentanil: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when remifentanil is used concomitantly with an anticholinergic drug. The concomitant use of remifentanil and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Revefenacin: (Moderate) Although revefenacin is minimally absorbed into the systemic circulation after inhalation, there is the potential for additive anticholinergic effects when administered with other antimuscarinics. Avoid concomitant administration with other anticholinergic and antimucarinic medications.
RimabotulinumtoxinB: (Moderate) The use of systemic antimuscarinic/anticholinergic agents following the administration of botulinum toxins may result in a potentiation of systemic anticholinergic effects (e.g., blurred vision, dry mouth, constipation, or urinary retention).
Rivastigmine: (Moderate) The therapeutic benefits of rivastigmine, a cholinesterase inhibitor, may be diminished during chronic co-administration with antimuscarinics or medications with potent anticholinergic activity. When concurrent use is not avoidable, the patient should be monitored for cognitive decline and anticholinergic side effects. Clinicians should generally avoid multiple medications with anticholinergic activity in the patient with dementia. Some of the common selective antimuscarinic drugs for bladder problems, (such as oxybutynin, darifenacin, trospium, fesoterodine, tolerodine, or solifenacin), do not routinely cause problems with medications used for dementia, but may cause anticholinergic side effects in some patients. Atropine may be used to offset bradycardia in cholinesterase inhibitor overdose.
Secretin: (Major) Discontinue anticholinergic medications at least 5 half-lives before administering secretin. Patients who are receiving anticholinergics at the time of stimulation testing may be hyporesponsive to secretin stimulation and produce a false result. Consider additional testing and clinical assessments for aid in diagnosis.
Sedating H1-blockers: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by anticholinergics. False study results are possible in patients with drug-induced hyper- or hypo-responsiveness; thorough patient history is important in the interpretation of procedure results.
Sodium Sulfate; Magnesium Sulfate; Potassium Chloride: (Moderate) Use anticholinergics, such as flavoxate, and concomitant solid oral dosage forms of potassium chloride with caution due to risk for gastrointestinal mucosal injury. Anticholinergics may decrease gastric motility and increase the transit time of solid oral dosage forms of potassium chloride leading to prolonged contact with the gastrointestinal mucosa.
Solifenacin: (Moderate) Additive anticholinergic effects may be seen when drugs with antimuscarinic properties like solifenacin are used concomitantly with other antimuscarinics. Blurred vision and dry mouth would be common effects. Clinicians should note that additive antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur.
Spironolactone; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Sufentanil: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when sufentanil is used concomitantly with an anticholinergic drug. The concomitant use of sufentanil and anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Tapentadol: (Moderate) Tapentadol should be used cautiously with anticholinergic medications since additive depressive effects on GI motility or bladder function may occur. Monitor patients for signs of urinary retention or reduced gastric motility. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect. Opiate analgesics combined with antimuscarinics can cause severe constipation or paralytic ileus, especially with chronic use. Additive CNS effects like drowsiness or dizziness may also occur.
Tegaserod: (Major) Drugs that exert significant anticholinergic properties such as antimuscarinics may pharmacodynamically oppose the effects of prokinetic agents such as tegaserod. Avoid administering antimuscarinics along with tegaserod under most circumstances. Inhaled respiratory antimuscarinics, such as ipratropium, are unlikely to interact with tegaserod. Ophthalmic anticholinergics may interact if sufficient systemic absorption of the eye medication occurs.
Telmisartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Tenapanor: (Moderate) Anticholinergics can promote constipation and pharmacodynamically oppose the action of drugs used for the treatment of constipation or constipation-associated irritable bowel syndrome, such as tenapanor.
Thiazide diuretics: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Thioridazine: (Moderate) Additive anticholinergic effects may be seen when drugs with anticholinergic properties like thioridazine are used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the interacting agent.
Thiothixene: (Moderate) Anticholinergics may have additive effects with thiothixene, an antipsychotic with the potential for anticholinergic activity. Monitor for anticholinergic-related adverse effects such as xerostomia, blurred vision, constipation, and urinary retention during concurrent use.
Tiotropium: (Major) Avoid concomitant use of anticholinergic medications and tiotropium due to increased risk for anticholinergic adverse effects.
Tiotropium; Olodaterol: (Major) Avoid concomitant use of anticholinergic medications and tiotropium due to increased risk for anticholinergic adverse effects.
Tolterodine: (Moderate) Additive anticholinergic effects may be seen when tolterodine is used concomitantly with other antimuscarinics. When possible, avoid concurrent use, especially in the elderly, who are more susceptible to the anticholinergic effects. Consider alternatives to these other medications, if available. Clinicians should note that antimuscarinic effects might be seen not only on bladder smooth muscle, but also on GI function, the eye, and temperature regulation. Blurred vision, constipation, and dry mouth may be more prominent additive effects. With many of the listed agents, additive drowsiness may also occur when combined.
Topiramate: (Moderate) Monitor for decreased sweating and increased body temperature, especially in hot weather, during concomitant use of topiramate and other drugs that predispose persons to heat-related disorders, such as anticholinergic medications. Concomitant use increases the risk for oligohidrosis and hyperthermia.
Tramadol: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant tramadol and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Tramadol; Acetaminophen: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant tramadol and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Triamterene; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Tricyclic antidepressants: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Trifluoperazine: (Moderate) Additive anticholinergic effects may be seen when anticholinergics are used concomitantly with phenothiazines, including trifluoperazine. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur.
Trimethobenzamide: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Trimipramine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Triprolidine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant sedating H1-blocker and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Trospium: (Moderate) Additive anticholinergic effects may be seen when trospium is used concomitantly with other antimuscarinics. When possible, avoid concurrent use, especially in the elderly, who are more susceptible to the anticholinergic effects. Consider alternatives to these other medications, if available. Clinicians should note that antimuscarinic effects might be seen not only on bladder smooth muscle, but also on GI function, the eye, and temperature regulation. Blurred vision, constipation, and dry mouth may be more prominent additive effects. With many of the listed agents, additive drowsiness may also occur when combined with trospium.
Umeclidinium: (Moderate) There is the potential for umeclidinium to have additive anticholinergic effects when administered with other anticholinergics or antimuscarinics. Per the manufaturer, avoid concomitant administration of umeclidinium with other anticholinergic medications when possible.
Umeclidinium; Vilanterol: (Moderate) There is the potential for umeclidinium to have additive anticholinergic effects when administered with other anticholinergics or antimuscarinics. Per the manufaturer, avoid concomitant administration of umeclidinium with other anticholinergic medications when possible.
Valsartan; Hydrochlorothiazide, HCTZ: (Minor) Coadministration of thiazides and antimuscarinics (e.g., atropine and biperiden) may result in increased bioavailability of the thiazide. This is apparently a result of a decrease in gastrointestinal motility and rate of stomach emptying by the antimuscarinic agent. In addition, diuretics can increase urinary frequency, which may aggravate bladder symptoms.
Vibegron: (Moderate) Vibegron should be administered with caution in patients taking anticholinergics because of potential for an increased risk of urinary retention. Monitor for symptoms of urinary difficulties or urinary retention. Patients may note constipation or dry mouth with use of these drugs together.
Zonisamide: (Moderate) Zonisamide use is associated with case reports of decreased sweating, hyperthermia, heat intolerance, or heat stroke and should be used with caution in combination with other drugs that may also predispose patients to heat-related disorders like anticholinergics.
Flavoxate has direct spasmolytic actions on smooth muscle, especially of the urinary tract. Administration of flavoxate relaxes smooth muscles of the urinary tract (i.e., the detrusor muscle) thereby reducing symptoms associated with bladder spasticity. Urinary bladder capacity is also increased. Flavoxate also has weak antihistaminic, local anesthetic, and analgesic properties. High doses of the drug can produce weak anticholinergic actions.
Flavoxate is administered orally. Metabolism of flavoxate is unknown. Excretion is via the kidneys with approximately 10-30% of a flavoxate dose is excreted in urine within 6 hours of dosing and 57% being excreted within 24 hours of dosing.
-Route-Specific Pharmacokinetics
Oral Route
Following oral administration the drug appears to be well absorbed from the gastrointestinal tract. In healthy males, the onset of action of flavoxate is about 55 minutes with peak plasma concentrations occurring within 2 hours.
-Special Populations
Renal Impairment
It is not known whether flavoxate is removed by dialysis.