Aluminum hydroxide; magnesium carbonate is an oral combination product used as an antacid for temporary relief of symptoms associated with gastric acidity. The side effects of constipation from aluminum and diarrhea from magnesium are dose related, and the combination of aluminum hydroxide and magnesium carbonate allows for a potent acid neutralizing capacity with lower doses of each agent. Aluminum and magnesium combinations are the most commonly used commercial antacids. Aluminum hydroxide; magnesium carbonate is commercially available in an oral suspension and oral tablet form. Some products also contain the ingredient alginic acid that creates a viscous foam barrier that floats on the top of stomach contents. This is purported to be useful in gastroesophageal reflux, although the FDA considers alginic acid to be of questionable value. Gaviscon(R) Regular Strength Liquid was approved by the FDA in 1978; Gaviscon(R) Extra Strength Tablets were approved by the FDA in 1988; and Gaviscon(R) Extra Strength Liquid was approved by the FDA in 1989.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
NOTE: The composition of available aluminum hydroxide; magnesium carbonate products (i.e., chewable tablets and oral suspension) is variable. For individual composition see Product Information.
-Usual administration is as soon as symptoms occur, after meals, and at bedtime.
-Do not administer concurrently with other oral medications; see Drug Interactions for specific guidance on dosing separation.
Oral Solid Formulations:
-Chewable tablets: Chew thoroughly before swallowing and follow with a half to full glass of water.
Oral Liquid Formulations:
-Suspension: Shake well prior to administration. Measure dosage with a calibrated device. Follow dose with a full glass of water.
Aluminum hydroxide; magnesium carbonate administration is associated with diarrhea, constipation, chalky taste, diuresis, dehydration, nausea, and vomiting.
Patients who are dehydrated, fluid restricted, or have preexisting decreased bowel motility are predisposed to developing GI obstruction due to the aluminum in aluminum hydroxide; magnesium carbonate. Hemorrhoids, fecal impaction, and/or fissures are other complications associated with antacid use in patients with preexisting conditions.
With prolonged use, the aluminum in aluminum hydroxide; magnesium carbonate causes an increase in bone resorption and an increase in the intestinal absorption of calcium, possibly leading to hypercalcemia.
If aluminum hydroxide; magnesium carbonate is used in patients with impaired renal function or at high doses for extended periods of time, patients are at risk for developing hypermagnesemia and accumulating aluminum in the bones, lungs, and nerve tissues. Hypermagnesemia results in a depressant effect on the central nervous system (causing anorexia and nausea) and the neuromuscular system (causing decreased deep tendon reflexes and skeletal muscle weakness). Hypotension, muscle weakness, and electrocardiographic changes are indicative of magnesium toxicity. The accumulation of aluminum can lead to dialysis encephalopathy, dialysis osteomalacia, or "dialysis dementia" (impaired cognition).
Hypophosphatemia can occur in patients receiving long-term aluminum hydroxide; magnesium carbonate therapy, due to the aluminum component. This reaction is especially likely to occur in patients who have an inadequate dietary intake of phosphate. Hypophosphatemia is characterized by anorexia, malaise, and muscle weakness. Prolonged aluminum hydroxide administration also can cause nephrolithiasis, osteomalacia, and osteoporosis.
Aluminum hydroxide; magnesium carbonate is contraindicated in patients with renal disease, including renal failure and severe renal impairment. It should be used cautiously in neonates, geriatric patients, and in patients with mild to moderate renal impairment because of the increased risk of developing hypermagnesemia and magnesium and/or aluminum toxicity. If administering in the presence of mild to moderate renal impairment, closely monitor serum magnesium levels and watch for signs and symptoms of toxicity.
Use aluminum hydroxide; magnesium carbonate products with caution in patients on sodium restricted diets and in those with congestive heart failure, edema, or cirrhosis with ascites (severe hepatic disease) as the total daily dose may exceed 5 mEq (115 mg) of sodium.
Aluminum hydroxide; magnesium carbonate is not recommended for use in patients with ulcerative colitis, which can be aggravated by the laxative effect of magnesium-containing antacids. Aluminum hydroxide; magnesium carbonate is not recommended for use in patients with colostomy, diverticulitis, or ileostomy because of an increased risk of developing electrolyte imbalance.
Patients with constipation, fecal impaction, GI obstruction, ileus, hemorrhoids, or undiagnosed rectal or GI bleeding should receive aluminum hydroxide; magnesium carbonate with caution; it is possible that these conditions could be aggravated or that the patient could develop sepsis, peritonitis, or ischemic bowel.
Aluminum hydroxide; magnesium carbonate should be used with caution in patients with chronic diarrhea. Diarrhea can be aggravated by the laxative effect of the magnesium component and diarrhea increases the risk of developing hypophosphatemia associated with the aluminum component.
When used occasionally at recommended doses, aluminum and magnesium containing antacids are generally considered safe during pregnancy, provided the pregnant individual does not have concerns with renal dysfunction. Guidelines recommend a trial of lifestyle modifications as first-line therapy for heartburn and gastroesophageal reflux disease (GERD), followed by antacids. For ongoing symptoms, histamine type 2-receptor antagonists (H2RAs) can be used to control heartburn symptoms in pregnancy. Proton pump inhibitors should be reserved for patients who fail H2RA therapy.
When chronic use and high doses are avoided, aluminum hydroxide; magnesium carbonate appears to be safe and effective for the relief of dyspepsia and heartburn/gastroesophageal reflux (GERD) during breast-feeding. No problems have been reported in the breastfed infant and these antacids do not concentrate in breast milk.
Over-the-counter use of aluminum hydroxide; magnesium carbonate is not recommended as an antacid in infants and children < 2 years without supervision of a physician due to the serious nature of the complications associated with reflux in infants (such as failure to thrive, esophageal stricture, Barrett's esophagus, intraesophageal polyps, and associated pulmonary diseases). Aluminum hydroxide; magnesium carbonate has been used in children for esophagitis and peptic ulcer disease, although safety has not been clearly established.
For symptomatic relief of dyspepsia, pyrosis (heartburn), or symptoms associated with gastroesophageal reflux disease (GERD):
Oral dosage (suspension containing 95 mg of aluminum hydroxide and 358 mg of magnesium carbonate per 15 mL):
Adults: 15 to 30 mL (95 to 190 mg aluminum hydroxide; 358 to 716 mg magnesium carbonate) PO 4 times daily as needed. Max: 120 mL/day (760 mg/day aluminum hydroxide; 2,864 mg/day magnesium carbonate).
Oral dosage (suspension containing 254 mg of aluminum hydroxide and 237.5 mg of magnesium carbonate per 5 mL):
Adults: 10 to 20 mL (508 to 1,016 mg aluminum hydroxide; 475 to 950 mg magnesium carbonate) PO 4 times daily as needed. Max: 80 mL/day (4,064 mg/day aluminum hydroxide; 3,800 mg/day magnesium carbonate).
Children and Adolescents 12 to 17 years: 10 to 20 mL (508 to 1,016 mg aluminum hydroxide; 475 to 950 mg magnesium carbonate) PO 4 times daily as needed. Max: 80 mL/day (4,064 mg/day aluminum hydroxide; 3,800 mg/day magnesium carbonate).
Oral dosage (chewable tablets containing 160 mg of aluminum hydroxide and 105 mg of magnesium carbonate):
Adults: 2 to 4 tablets (320 to 640 mg aluminum hydroxide; 210 to 420 mg magnesium carbonate) PO 4 times daily as needed. Max: 16 tablets/day (2,560 mg/day aluminum hydroxide; 1,680 mg/day magnesium carbonate).
Maximum Dosage Limits:
Consult package label; maximum daily dosage is age and product specific. Do not exceed recommended daily dosage in any 24 hour period.
Patients with Hepatic Impairment Dosing
No specific dosage adjustment appears needed, unless the patient also has declining renal function (see below). The daily sodium intake from the antacid may need to be considered in patients with ascites.
Patients with Renal Impairment Dosing
CrCl >= 25 mL/min: Patients with renal impairment may be at risk of accumulating aluminum and magnesium. However, no dosage guidelines are available.
CrCl 10-25 mL/min: Patients with renal impairment may be at risk of accumulating aluminum and magnesium. However, no dosage guidelines are available; serum magnesium monitoring is recommended if aluminum hydroxide; magnesium carbonate must be used.
CrCl < 10 mL/min: Avoid use in renal failure.
*non-FDA-approved indication
Abacavir; Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain aluminum which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.
Acalabrutinib: (Moderate) Separate the administration of acalabrutinib capsules and antacids by at least 2 hours if these agents are used together. Acalabrutinib capsules solubility decreases with increasing pH values; therefore, coadministration may result in decreased acalabrutinib exposure and effectiveness. In healthy subjects, the AUC of acalabrutinib was decreased by 53% when acalabrutinib was coadministered with another antacid.
Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Aspirin, ASA; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Aspirin: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Aspirin; Diphenhydramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Caffeine; Dihydrocodeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Caffeine; Pyrilamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Chlorpheniramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Codeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Dextromethorphan: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Dextromethorphan; Doxylamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Acetaminophen; Dextromethorphan; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Acetaminophen; Diphenhydramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Guaifenesin; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Hydrocodone: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Ibuprofen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Oxycodone: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Pamabrom; Pyrilamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Acetaminophen; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Acetohydroxamic Acid: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
Acidifying Agents: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
Acrivastine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Albuterol; Budesonide: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.
Alendronate: (Moderate) Separate administration of alendronate and aluminum hydroxide by at least 30 minutes. Aluminum-containing antacids will interfere with the absorption of alendronate.
Alendronate; Cholecalciferol: (Moderate) Separate administration of alendronate and aluminum hydroxide by at least 30 minutes. Aluminum-containing antacids will interfere with the absorption of alendronate.
Allopurinol: (Minor) Aluminum hydroxide decreases the oral bioavailability of allopurinol, possibly by inhibiting gastrointestinal absorption of allopurinol. Allopurinol should be administered no less than 3 hours before doses of aluminum hydroxide to avoid inhibition of allopurinol absorption.
Amphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Amphetamine; Dextroamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Amphetamines: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Anticholinergics: (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.
Ascorbic Acid, Vitamin C: (Minor) Because antacids can alkalinize the urine, they can interact with urinary acidifiers, such as ascorbic acid. Frequent use of high doses of antacids should be avoided by patients receiving urinary acidifiers.
Aspirin, ASA; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Atazanavir: (Major) It is recommended that antacids not be given at the some time as atazanavir because of potential interference with absorption of atazanavir. Separate the administration of atazanavir and antacids to avoid the potential for interaction; give atazanavir 2 hours before or 1 hour after the antacid.
Atazanavir; Cobicistat: (Major) It is recommended that antacids not be given at the some time as atazanavir because of potential interference with absorption of atazanavir. Separate the administration of atazanavir and antacids to avoid the potential for interaction; give atazanavir 2 hours before or 1 hour after the antacid.
Atenolol: (Minor) Aluminum hydroxide antacids have been reported to decrease atenolol mean peak concentrations by about 20% and the AUC of atenolol by 57%. In another study, antacids have been shown to reduce the AUC of atenolol by 33%. Separate doses of atenolol and aluminum-containing antacids or supplements when possible by at least 2 hours to minimize this potential interaction. However, most clinicians consider the interaction of atenolol with antacids to be of minor clinical significance, since clinical efficacy (heart rate and blood pressure parameters) appear to be unchanged under usual intermittent clinical use.
Atenolol; Chlorthalidone: (Minor) Aluminum hydroxide antacids have been reported to decrease atenolol mean peak concentrations by about 20% and the AUC of atenolol by 57%. In another study, antacids have been shown to reduce the AUC of atenolol by 33%. Separate doses of atenolol and aluminum-containing antacids or supplements when possible by at least 2 hours to minimize this potential interaction. However, most clinicians consider the interaction of atenolol with antacids to be of minor clinical significance, since clinical efficacy (heart rate and blood pressure parameters) appear to be unchanged under usual intermittent clinical use.
Atropine: (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.
Atropine; Difenoxin: (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.
Azithromycin: (Moderate) Separate administration of immediate-release azithromycin and aluminum- and magnesium-containing antacids by 2 hours. Coadministration may decrease the absorption of azithromycin which may decrease its efficacy. The extended-release suspension may be taken without regard to antacids containing aluminum or magnesium.
Baloxavir Marboxil: (Major) Do not administer baloxavir with products that contain aluminum hydroxide. Polyvalent cations, such as aluminum, can chelate with baloxavir; thereby reducing its absorption. (Major) Do not administer baloxavir with products that contain magnesium carbonate. Polyvalent cations, such as magnesium, can chelate with baloxavir, reducing its absorption.
Belladonna; Opium: (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.
Bempedoic Acid; Ezetimibe: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.
Benzhydrocodone; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (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.
Benzphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Benztropine: (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.
Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Administer bictegravir on an empty stomach 2 hours before or 6 hours after taking antacids containing aluminum or magnesium. Routine administration of bictegravir simultaneously with, or 2 hours after, antacids containing aluminum or magnesium is not recommended as the bioavailability of bictegravir may be reduced. In drug interaction studies, simultaneous administration of bictegravir and antacids under fasted and fed conditions decreased the mean AUC of bictegravir by approximately 79% and 47%, respectively.
Bisacodyl: (Minor) The concomitant use of bisacodyl tablets with antacids can cause the enteric coating of the bisacody tablet to dissolve prematurely, leading to possible gastric irritation or dyspepsia. Avoid antacids within 1 hour before or after the bisacodyl dosage.
Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.
Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.
Bosutinib: (Moderate) Bosutinib displays pH-dependent aqueous solubility; therefore, concomitant use of bosutinib and antacids may result in decreased plasma exposure of bosutinib. Separate the administration of bosutinib and antacids by more than 2 hours.
Brompheniramine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Budesonide: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.
Budesonide; Formoterol: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.
Budesonide; Glycopyrrolate; Formoterol: (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. (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.
Butalbital; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Butalbital; Acetaminophen; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Butalbital; Acetaminophen; Caffeine; Codeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Cabotegravir: (Moderate) Administer antacids at least two hours before or four hours after taking oral cabotegravir. The chemical structure of these antacids contains aluminum or magnesium which can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir.
Cabotegravir; Rilpivirine: (Moderate) Administer antacids at least two hours before or four hours after taking oral cabotegravir. The chemical structure of these antacids contains aluminum or magnesium which can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir. (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.
Captopril: (Major) Antacids can decrease the GI absorption of captopril if administered simultaneously.
Captopril; Hydrochlorothiazide, HCTZ: (Major) Antacids can decrease the GI absorption of captopril if administered simultaneously.
Cefdinir: (Moderate) Antacids containing magnesium or aluminum can interfere with the absorption of cefdinir. If aluminum or magnesium containing antacids are required during cefdinir therapy, cefdinir should be taken at least 2 hours before or after the antacid.
Cefpodoxime: (Moderate) Cefpodoxime proxetil requires a low gastric pH for dissolution; therefore, concurrent administration with medications that increase gastric pH (e.g., antacids) may decrease the bioavailability of cefpodoxime. Concomitant administration with high doses of antacids reduces peak plasma concentrations by 24% and the extent of absorption by 27%. The rate of absorption is not affected.
Cefuroxime: (Moderate) Antacids can interfere with the oral absorption of cefuroxime axetil and may result in reduced antibiotic efficacy. If an antacid must be used while a patient is taking cefuroxime, administer the oral dosage of cefuroxime at least 1 hour before or 2 hours after the antacid.
Cetirizine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Chenodiol: (Moderate) Aluminum hydroxide based antacids have been shown to adsorb bile acids in vitro and are expected to interfere with the efficacy of chenodiol. To minimize drug interactions, administer chenodiol at least 1 hour before or at least 2 hours after the aluminum-based antacid.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Chlordiazepoxide; Clidinium: (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.
Chloroquine: (Major) Chloroquine absorption may be reduced by antacids. Administer chloroquine and antacids at least 4 hours apart.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Chlorpheniramine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Chlorpromazine: (Moderate) The absorption of chlorpromazine liquids, suspensions, or concentrates may be decreased by co-administration of antacids. It may be advisable to separate chlorpromazine administration from antacids by 1 to 2 hours. In a small study (n = 6), administration of a magnesium trisilicate and aluminum hydroxide liquid gel antacid with a chlorpromazine liquid suspension resulted in a statistically significant decrease in chlorpromazine concentrations (average 20% decline; approximate range: 6% to 48%). In another kinetic study (n = 10), concurrent use of chlorpromazine liquid concentrate and an aluminum and magnesium hydroxide suspension reduced the urinary excretion of chlorpromazine by 10% to 45%. Adsorption of chlorpromazine to the antacid suspension may have contributed to a subsequent decline in urinary excretion of the drug.
Cholic Acid: (Moderate) Do not administer cholic acid simultaneously with aluminum-based antacids (i.e., aluminum hydroxide) because a reduction in cholic acid absorption will occur. Administer cholic acid at least 1 hour before or 4 to 6 hours (or the maximal interval possible) after an aluminum-based antacids.
Ciprofloxacin: (Moderate) Administer oral ciprofloxacin at least 2 hours before or 6 hours after magnesium carbonate. Ciprofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. (Moderate) Administer oral ciprofloxacin at least 2 hours before or 6 hours after products that contain aluminum hydroxide. Ciprofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids that contain aluminum hydroxide.
Citric Acid; Potassium Citrate; Sodium Citrate: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage. (Major) Avoid coadministration of aluminum hydroxide with citrate salts due to the potential for increased absorption of aluminum. Patients at increased risk of aluminum accumulation include patients with renal impairment or renal failure.
Codeine; Guaifenesin; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Conjugated Estrogens; Bazedoxifene: (Minor) In clinical evaluation, a single dose of 460 mg aluminum hydroxide and 400 mg magnesium hydroxide was given with a bazedoxifene 40 mg tablet in 30 postmenopausal women after an overnight fast. Coadministration of aluminum/magnesium hydroxide and bazedoxifene decreased Cmax of bazedoxifene by 8% and increased AUC of bazedoxifene by 7%. The clinical effect of this change is not known, but appears to be clinically insignificant. Separating times of administration may help limit any possible interaction.
Cysteamine: (Major) In general, cysteamine may be administered with electrolyte and mineral replacements necessary for managing Fanconi syndrome, as well as with vitamin D and thyroid hormone. However, delayed-release cysteamine (Procysbi) should be administered at least 1 hour before or 1 after medications that increase gastric pH, including those containing bicarbonate or carbonate (i.e., magnesium carbonate). Drugs that increase the gastric pH, such as bicarbonate and carbonate, may cause the premature release of cysteamine from delayed-release capsules, leading to an increase in WBC cystine concentration.
Dasatinib: (Moderate) Separate the administration of dasatinib and antacids by at least 2 hours if these agents are used together. The simultaneous administration of an antacid with dasatinib decreased the Cmax and AUC of dasatinib by 58% and 55%, respectively.
Deferasirox: (Moderate) Although deferasirox has a lower affinity for aluminum than for iron, deferasirox may also increase the excretion of aluminum. Because deferasirox may bind to aluminum instead of iron, aluminum containing antacids should not be administered concurrently in order to avoid a possible decreased efficacy of either therapy.
Deferiprone: (Moderate) Concurrent use of deferiprone with food, mineral supplements, and antacids that contain polyvalent (trivalent) cations has not been studied. However, since deferiprone has the potential to bind polyvalent cations (e.g., iron, aluminum, and zinc), allow at least a 4-hour interval between deferiprone and other medications or dietary supplements containing these polyvalent cations. Such medications can include antacids, iron salts, aluminum hydroxide, dietary supplements containing polyvalent minerals, and zinc salts.
Delafloxacin: (Major) Administer oral delafloxacin at least 2 hours before or 6 hours after products that contain aluminum hydroxide. Delafloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids containing aluminum hydroxide.
Delavirdine: (Major) Coadministration of delavirdine with antacids results in decreased absorption of delavirdine. Administration of delavirdine and antacids should be separated by at least 1 hour.
Demeclocycline: (Moderate) Separate administration of demeclocycline and antacids by 2 to 3 hours. Coadministration may impair absorption of demeclocycline which may decrease its efficacy.
Desloratadine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Dexbrompheniramine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Dextroamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Dextromethorphan; Quinidine: (Major) Alkalinizing agents such as antacids can increase renal tubular reabsorption of quinidine by alkalinizing the urine; higher quinidine serum concentrations and quinidine toxicity are possible.
Diazepam: (Moderate) The coadministration of diazepam with antacids results in delayed diazepam absorption due to the fact that antacids delay gastric emptying. It may be prudent to separate dosing by 2 hours to limit any potential interaction.
Dicyclomine: (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.
Didanosine, ddI: (Minor) The side effects associated with aluminum hydroxide may potentially be increased during concurrent use with didanosine, ddI because some ddI products also contain similar antacid ingredients. (Minor) The side effects associated with magnesium carbonate may potentially be increased during concurrent use with didanosine, ddI because some ddI products also contain similar antacid ingredients. Although this interaction should be of minor clinical significance for most patients, clinicians should be alert to a possible increased risk of side effects associated with taking an additional antacid product concurrently with ddI products.
Diflunisal: (Moderate) Concurrent use of diflunisal with antacids may reduce plasma diflunisal concentrations. The effect may be clinically significant if antacids are used on a continuous schedule.
Digoxin: (Moderate) Monitor digoxin concentrations as appropriate and watch for decreased digoxin efficacy if coadministration with antacids is necessary. The dose of digoxin may need to be adjusted. Antacids may decrease the absorption of digoxin.
Diphenhydramine; Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.
Diphenoxylate; Atropine: (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.
Dolutegravir: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain aluminum which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.
Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain aluminum which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.
Dolutegravir; Rilpivirine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain aluminum which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.
Doxycycline: (Moderate) Separate administration of oral doxycycline and antacids by 2 to 3 hours. Coadministration may impair absorption of doxycycline which may decrease its efficacy.
Eltrombopag: (Major) Eltrombopag chelates polyvalent cations (e.g., calcium, aluminum, and magnesium) in food, mineral supplements, and antacids. In a clinical study, systemic exposure to eltrombopag was decreased by 70% when it was administered with a polyvalent cation-containing antacid. Administer eltrombopag at least 2 hours before or 4 hours after any oral products containing polyvalent cations, such as aluminum salts, (like aluminum hydroxide), calcium salts, (including calcium carbonate), and magnesium salts.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Separate administration of elvitegravir and antacids by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Separate administration of elvitegravir and antacids by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.
Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.
Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.
Erdafitinib: (Major) Avoid coadministration of aluminum hydroxide with erdafitinib before the initial dose increase period (days 14 to 21) which is based on serum phosphate levels. Aluminum hydroxide decreases serum phosphate levels. The initial dose increase of erdafitinib on days 14 to 21 is based on serum phosphate levels; changes in serum phosphate levels by aluminum hydroxide may interfere with the determination of this initial dose increase.
Erlotinib: (Major) Separate administration by several hours if concomitant use of erlotinib and antacids is necessary. Erlotinib displays pH-dependent solubility with decreased solubility at a higher pH; the increased gastric pH resulting from antacid therapy may reduce the bioavailability of erlotinib. Increasing the dose of erlotinib without modifying the administration schedule is unlikely to compensate for loss of exposure. The effects of antacids on erlotinib pharmacokinetics has not been evaluated.
Ethambutol: (Moderate) Aluminum hydroxide can reduce the rate or extent of ethambutol absorption. At least 4 hours should elapse between doses of aluminum hydroxide-containing antacids and ethambutol.
Ethotoin: (Major) Aluminum hydroxide inhibits the absorption of ethotoin. Simultaneous administration should be avoided; separate dosing by at least 2 hours to limit an interaction.
Etidronate: (Moderate) Separate administration of oral etidronate and aluminum hydroxide by at least 2 hours. Aluminum-containing antacids will interfere with the absorption of oral etidronate.
Ezetimibe: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.
Ezetimibe; Simvastatin: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.
Ferric Maltol: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Fexofenadine: (Moderate) Coadministration with antacids (containing aluminum or magnesium) within 15 minutes decreases the AUC and Cmax of fexofenadine by 41% and 43%, respectively. Separate administration is recommended.
Fexofenadine; Pseudoephedrine: (Moderate) Coadministration with antacids (containing aluminum or magnesium) within 15 minutes decreases the AUC and Cmax of fexofenadine by 41% and 43%, respectively. Separate administration is recommended. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Flavoxate: (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.
Fosamprenavir: (Moderate) Administer fosamprenavir at least 1 hour before or 1 hour after antacids. Coadministration may decrease the exposure of fosamprenavir and impair its efficacy.
Fosinopril: (Moderate) Coadministration of antacids with fosinopril may impair absorption of fosinopril. Therefore, if concomitant administration of these agents is indicated, dosing should be separated by 2 hours.
Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Coadministration of antacids with fosinopril may impair absorption of fosinopril. Therefore, if concomitant administration of these agents is indicated, dosing should be separated by 2 hours.
Gabapentin: (Moderate) Gabapentin should be taken at least 2 hours after the administration of antacids. Antacids have been shown to reduce the oral bioavailability of gabapentin by roughly 20%. This decrease in bioavailability was about 5% when gabapentin was administered 2 hours after the antacid.
Gastrointestinal Enzymes: (Major) The effectiveness of gastrointestinal enzymes can be diminished with concurrent administration of antacids. In-vitro studies suggest that calcium and magnesum cations exert their deleterious effect on replacement enzyme therapy by formation of poorly soluble calcium or magnesium soaps and precipitation of glycine conjugated bile salts.
Gefitinib: (Major) Avoid coadministration of antacids with gefitinib if possible due to decreased exposure to gefitinib, which may lead to reduced efficacy. If concomitant use is unavoidable, take gefitinib 6 hours after the last dose or 6 hours before the next antacid dose. Gefitinib exposure is affected by gastric pH. Coadministration with another drug to maintain gastric pH above 5 decreased gefitinib exposure by 47%.
Gemifloxacin: (Major) Administer products that contain aluminum hydroxide at least 3 hours before or 2 hours after gemifloxacin. Gemifloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids that contain aluminum hydroxide. (Major) Unlike most oral quinolones, oral gemifloxacin may be administered without regard to food; calcium does not appear to appreciably affect the bioavailability of the oral dosage form. Most quinolones are susceptible to oral chelation interactions with selected cations. The oral absorption of gemifloxacin may be significantly reduced by other orally administered multivalent cations such as aluminum salts (e.g., aluminum hydroxide) and magnesium salts. Examples of compounds that may interfere with fluoroquinolone bioavailability include most antacids (including combination antacids containing aluminum or magnesium, but not calcium carbonate); magnesium citrate; magnesium salicylate; and multivitamins that contain magnesium. Calcium carbonate (1000 mg) given either 2 hr before or 2 hr after gemifloxacin administration did not notably reduce oral gemifloxacin systemic availability. Calcium carbonate administered simultaneously with gemifloxacin resulted in a small, but not clinically significant, decrease in gemifloxacin AUC by 21% and Cmax. Significant pharmacokinetic interactions can occur when Maalox (aluminum hydroxide; magnesium hydroxide) is administered with gemifloxacin. Maalox given 10 minutes before gemifloxacin reduced the gemifloxacin AUC by approximately 85%; Maalox 3 hours after gemifloxacin resulted in a 15% gemifloxacin AUC reduction. No effect on gemifloxacin AUC was observed when Maalox was given 2 hours before the antimicrobial agent. It is not yet clear if bismuth subsalicylate (Pepto-Bismol) can interfere with fluoroquinolone bioavailability. To help avoid interactions due to chelation, gemifloxacin should be taken at least 3 hours before or 2 hours after administration of a potential interfering agent.
Glipizide: (Moderate) Antacids have been reported to increase the absorption of glipizide, enhancing its hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If these drugs must be used together, give glipizide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.
Glipizide; Metformin: (Moderate) Antacids have been reported to increase the absorption of glipizide, enhancing its hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If these drugs must be used together, give glipizide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.
Glyburide: (Moderate) Antacids have been reported to increase the absorption of non-micronized glyburide, enhancing their hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If antacids must be used while a patient is taking glyburide, give the glyburide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.
Glyburide; Metformin: (Moderate) Antacids have been reported to increase the absorption of non-micronized glyburide, enhancing their hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If antacids must be used while a patient is taking glyburide, give the glyburide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.
Glycopyrrolate: (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.
Glycopyrrolate; Formoterol: (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.
Guaifenesin; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Homatropine; Hydrocodone: (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.
Hydroxychloroquine: (Moderate) Hydroxychloroquine absorption may be reduced by antacids as has been observed with the structurally similar chloroquine. Administer hydroxychloroquine and antacids at least 4 hours apart. Of note, a study demonstrated no significant difference in hydroxychloroquine serum concentration in patients taking concomitant antacids (n = 14) compared to those not taking antacids (n = 495).
Hyoscyamine: (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.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (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.
Ibandronate: (Moderate) Separate administration of oral ibandronate and aluminum hydroxide by at least 1 hour. Aluminum-containing antacids will interfere with the absorption of oral ibandronate.
Ibritumomab Tiuxetan: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
Ibuprofen; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Indacaterol; Glycopyrrolate: (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.
Indomethacin: (Moderate) Antacids may inhibit the oral absorption of indomethacin. Simultaneous administration should be avoided; separate dosing by at least 2 hours to limit an interaction.
Infigratinib: (Moderate) Separate the administration of infigratinib and locally acting antacids if concomitant use is necessary. Coadministration may decrease infigratinib exposure resulting in decreased efficacy. Administer infigratinib two hours before or after an antacid.
Iron Salts: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Iron: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.
Isoniazid, INH; Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.
Itraconazole: (Moderate) When administering antacids with the 100 mg itraconazole capsule and 200 mg itraconazole tablet formulations, systemic exposure to itraconazole is decreased. Conversely, exposure to itraconazole is increased when antacids are administered with the 65 mg itraconazole capsule. Administer antacids at least 2 hours before or 2 hours after the 100 mg capsule or 200 mg tablet. Monitor for increased itraconazole-related adverse effects if antacids are administered with itraconazole 65 mg capsules.
Ketoconazole: (Moderate) Administer antacids at least 1 hour before or 2 hours after taking ketoconazole. Antacids can impair the absorption of ketoconazole.
Lactulose: (Major) In general, other laxatives should not be used concurrently with lactulose, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved. Studies suggest that oral, nonabsorbable antacids and/or laxatives like magnesium hydroxide can interfere with the decrease in colon pH necessary for lactulose's action and these alterations may make it challenging to titrate an accurate dose of lactulose during treatment of hepatic encephalopathy.
Ledipasvir; Sofosbuvir: (Moderate) Separate administration of ledipasvir and antacids by at least 4 hours. Solubility of ledipasvir decreases as gastric pH increases; thus, simultaneous administration of these drugs may result in lower ledipasvir plasma concentrations.
Levofloxacin: (Moderate) Administer magnesium carbonate at least 2 hours before or 2 hours after orally administered levofloxacin. Levofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Chelation of divalent cations with levofloxacin is less than with other quinolones. (Moderate) Administer products that contain aluminum hydroxide at least 2 hours before or 2 hours after orally administered levofloxacin. Levofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Chelation of divalent cations with levofloxacin is less than with other quinolones. Examples of compounds that may interfere with quinolone bioavailability include antacids that contain aluminum hydroxide.
Levoketoconazole: (Moderate) Administer antacids at least 1 hour before or 2 hours after taking ketoconazole. Antacids can impair the absorption of ketoconazole.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Levothyroxine: (Moderate) To minimize an interaction, administer thyroid hormones at least 4 hours before or after antacids or other drugs containing aluminum hydroxide. Aluminum hydroxide, often found in antacids, interferes with the intestinal absorption of thyroid hormones. Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Levothyroxine; Liothyronine (Porcine): (Moderate) To minimize an interaction, administer thyroid hormones at least 4 hours before or after antacids or other drugs containing aluminum hydroxide. Aluminum hydroxide, often found in antacids, interferes with the intestinal absorption of thyroid hormones. Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Levothyroxine; Liothyronine (Synthetic): (Moderate) To minimize an interaction, administer thyroid hormones at least 4 hours before or after antacids or other drugs containing aluminum hydroxide. Aluminum hydroxide, often found in antacids, interferes with the intestinal absorption of thyroid hormones. Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Liothyronine: (Moderate) To minimize an interaction, administer thyroid hormones at least 4 hours before or after antacids or other drugs containing aluminum hydroxide. Aluminum hydroxide, often found in antacids, interferes with the intestinal absorption of thyroid hormones. Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Lisdexamfetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Loratadine; Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Mefenamic Acid: (Moderate) Ingestion of mefenamic acid with antacids is not recommended. Administration with an antacid containing 1.7 grams of magnesium hydroxide resulted in a 36 percent increase in the area under the time versus concentration curve of mefenamic acid.
Mefloquine: (Moderate) Antacids, H2-blockers, and proton pump inhibitors (PPIs) may increase plasma concentrations of mefloquine. In a small study involving 6 healthy subjects and 6 peptic ulcer patients, cimetidine increased the Cmax and AUC of mefloquine. In the study, the pharmacokinetics of mefloquine were determined after receiving a single oral mefloquine 500 mg dose alone and after 3-days of cimetidine 400 mg PO bid. In both healthy subjects and peptic ulcer patients, Cmax was increased 42.4% and 20.5%, respectively. The AUC was increased by 37.5% in both groups. Elimination half-life, total clearance, and volume of distribution were not significantly affected. An increase in adverse reactions was not noted. Patients on chronic mefloquine therapy might be at increased risk of adverse reactions, especially in patients with a neurological or psychiatric history.
Mesalamine, 5-ASA: (Moderate) Do not coadminister mesalamine extended-release capsules (Apriso) with antacids. Apriso is a pH-dependent, delayed-release capsule product with an enteric coating that dissolves at a pH of at least 6. Other mesalamine products do not have an interaction with antacids.
Methamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.
Methenamine: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (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.
Methenamine; Sodium Salicylate: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended.
Methscopolamine: (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.
Minocycline: (Moderate) Separate administration of minocycline and antacids by 2 to 3 hours. Coadministration may impair absorption of minocycline which may decrease its efficacy.
Moxifloxacin: (Major) Administer oral moxifloxacin at least 4 hours before or 8 hours after products that contain aluminum hydroxide. Moxifloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids that contain aluminum hydroxide. (Major) Similar to gatifloxacin, but unlike most fluoroquinolones, no clinically significant pharmacokinetic interactions occur when moxifloxacin is administered concomitantly with milk or calcium carbonate. In healthy volunteers, calcium supplements had no significant effect on the AUC of moxifloxacin, however, the mean Cmax was slightly reduced and the time to Cmax was prolonged compared to moxifloxacin given alone. The oral absorption of moxifloxacin may be significantly reduced by other orally administered compounds that contain aluminum salts (like aluminum hydroxide), iron salts, magnesium salts, or zinc salts. Examples of compounds that may interfere with fluoroquinolone bioavailability include antacids (e.g., aluminum hydroxide, magnesium hydroxide, or combination antacids containing aluminum or magnesium); sucralfate; magnesium citrate; magnesium salicylate; iron supplements (e.g., polysaccharide-iron complex) and multivitamins that contain iron, magnesium, manganese, or zinc. It is not yet clear if bismuth subsalicylate (Pepto-Bismol) can interfere with fluoroquinolone bioavailability. Oral moxifloxacin should be taken at least 4 hours before or 8 hours after administration of the above agents.
Mycophenolate: (Major) Coadministration of mycophenolate mofetil with antacids decreases the bioavailability of mycophenolate mofetil. Aluminum/magnesium hydroxide antacids decrease the AUC of mycophenolic acid by about 17% when given as mycophenolate mofetil. Decreased absorption of mycophenolate (possible chelation) is the likely etiology for reduced systemic exposure. If antacids and mycophenolate need to be used together, separate administration times are recommended (do not give simultaneously).
Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.
Naproxen; Esomeprazole: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.
Naproxen; Pseudoephedrine: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours. (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Neostigmine; Glycopyrrolate: (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.
Neratinib: (Major) Administer neratinib at least 3 hours after administration of antacids if concomitant use is necessary due to decreased absorption and systemic exposure of neratinib; the solubility of neratinib decreases with increasing pH of the GI tract. The efficacy of neratinib may be decreased.
Nilotinib: (Moderate) If concomitant use of these agents is necessary, administer the antacid approximately 2 hours before or approximately 2 hours after the nilotinib dose. Nilotinib displays pH-dependent solubility with decreased solubility at a higher pH; therefore, concomitant use of nilotinib and antacids may result in decreased bioavailability of nilotinib. In a study in healthy subjects, there was no significant change in nilotinib pharmacokinetics when an antacid (aluminum hydroxide/magnesium hydroxide/simethicone) was administered approximately 2 hours before or approximately 2 hours after a single 400-mg nilotinib dose.
Nirogacestat: (Moderate) Separate the administration of nirogacestat and antacids by at least 2 hours. Simultaneous coadministration may impair nirogacestat absorption resulting in reduced exposure and efficacy.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Octreotide: (Moderate) Coadministration of oral octreotide with antacids may require increased doses of octreotide. Coadministration of oral octreotide with drugs that alter the pH of the upper GI tract, including antacids, may alter the absorption of octreotide and lead to a reduction in bioavailability.
Ofloxacin: (Moderate) Administer magnesium carbonate at least 2 hours before or 2 hours after ofloxacin. Ofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. (Moderate) Administer products that contain aluminum hydroxide at least 2 hours before or 2 hours after ofloxacin. Ofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids that contain aluminum hydroxide.
Omadacycline: (Moderate) Separate administration of omadacycline and antacids by 4 hours. Coadministration may impair absorption of omadacycline which may decrease its efficacy.
Oxybutynin: (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.
Pancrelipase: (Major) The effectiveness of gastrointestinal enzymes can be diminished with concurrent administration of antacids. In-vitro studies suggest that calcium and magnesum cations exert their deleterious effect on replacement enzyme therapy by formation of poorly soluble calcium or magnesium soaps and precipitation of glycine conjugated bile salts.
Pazopanib: (Moderate) Separate administration of pazopanib and antacids by several hours if coadministration is necessary in order to avoid a reduction in pazopanib exposure, which may decrease efficacy.
Penicillamine: (Moderate) Because penicillamine chelates heavy metals, it is possible that antacids could reduce penicillamine bioavailability, which can decrease the therapeutic effects of penicillamine. Simultaneous administration should be avoided; separate dosing by at least 2 hours to limit an interaction.
Pexidartinib: (Moderate) Administer pexidartinib 2 hours before or after locally-acting antacids as concurrent administration may reduce pexidartinib exposure. Although the effects of locally-acting antacids on pexidartinib pharmacokinetics have not been studied, other acid-reducing agents have been shown to decrease pexidartinib exposure by 50%.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (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.
Phenytoin: (Moderate) Because the absorption of phenytoin suspension can be reduced by antacids containing magnesium, aluminum, or calcium, administration at the same time of day should be avoided when possible. Ingestion times of phenytoin capsules and calcium antacids should be staggered in patients with low serum phenytoin levels to prevent absorption difficulties. Studies evaluating the effects of magnesium-aluminium antacids on the absorption of phenytoin capsules or tablets have yielded conflicting results. Nevertheless, serum phenytoin levels and clinical response should be closely monitored if these agents are co-administered. The mechanisms by which antacids reduce phenytoin absorption may involve increased gastric transit time, chelation, adsorption, and/or altered solubility. The oral absorption of phenytoin may be reduced by calcium carbonate (e.g., as found in antacids) or other calcium salts. Calcium products may form complexes with phenytoin that are nonabsorbable. Although the magnitude of the interaction is not great, an occasional patient may be affected and the interaction may lead to subtherapeutic phenytoin concentrations. Separating the administration of phenytoin and antacids or calcium salts by at least 2 hours will help minimize the possibility of interaction.
Phosphorated Carbohydrate Solution: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
Phosphorus: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
Polyethylene Glycol; Electrolytes; Bisacodyl: (Minor) The concomitant use of bisacodyl tablets with antacids can cause the enteric coating of the bisacody tablet to dissolve prematurely, leading to possible gastric irritation or dyspepsia. Avoid antacids within 1 hour before or after the bisacodyl dosage.
Polysaccharide-Iron Complex: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Potassium Bicarbonate: (Major) Avoid coadministration of aluminum hydroxide with citrate salts due to the potential for increased absorption of aluminum. Patients at increased risk of aluminum accumulation include patients with renal impairment or renal failure.
Potassium Chloride: (Major) Avoid coadministration of aluminum hydroxide with citrate salts due to the potential for increased absorption of aluminum. Patients at increased risk of aluminum accumulation include patients with renal impairment or renal failure.
Potassium Citrate: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage. (Major) Avoid coadministration of aluminum hydroxide with citrate salts due to the potential for increased absorption of aluminum. Patients at increased risk of aluminum accumulation include patients with renal impairment or renal failure.
Potassium Citrate; Citric Acid: (Major) Avoid coadministration of aluminum hydroxide with citrate salts due to the potential for increased absorption of aluminum. Patients at increased risk of aluminum accumulation include patients with renal impairment or renal failure.
Potassium Phosphate: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
Potassium Phosphate; Sodium Phosphate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
Propantheline: (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.
Propranolol: (Moderate) Antacids may reduce the absorption of propranolol. The need to stagger doses of propranolol has not been established, but may be prudent. Monitor clinical response, and adjust propranolol dosage if needed to attain therapeutic goals.
Pseudoephedrine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Pseudoephedrine; Triprolidine: (Minor) It appears that antacids containing aluminum hydroxide may increase pseudoephedrine plasma concentrations. This interaction can be avoided by separating the administration of pseudoephedrine and antacids by 1 to 2 hours. If aluminum-based antacids are used on a regular basis, an alternative to pseudoephedrine may be considered.
Quinidine: (Major) Alkalinizing agents such as antacids can increase renal tubular reabsorption of quinidine by alkalinizing the urine; higher quinidine serum concentrations and quinidine toxicity are possible.
Quinine: (Major) Antacids may delay or decrease the absorption of quinine.
Raltegravir: (Major) Coadministration or staggered administration of aluminum and/or magnesium-containing antacids is not recommended during treatment with raltegravir. Coadministration may result in decreased plasma concentrations of raltegravir, which may lead to HIV treatment failure or the development of viral resistance. In a drug interaction study, the AUC for raltegravir was decreased by 49% (90% CI, 35% to 60%), 51% (90% CI, 33% to 65%), and 30% (90% CI, 4% to 50%), when administered with, 2 hours before, and 2 hours after aluminum/magnesium hydroxide antacids, respectively.
Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.
Rilpivirine: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.
Riociguat: (Major) Separate administration of riociguat from antacids by at least 1 hour. Antacids such as aluminum hydroxide/magnesium hydroxide decrease riociguat absorption.
Risedronate: (Moderate) Separate administration of oral risedronate and aluminum hydroxide by at least 2 hours. Aluminum-containing antacids will interfere with the absorption of oral risedronate.
Rosuvastatin: (Moderate) Coadministration of rosuvastatin with antacids has reduced rosuvastatin plasma concentrations by 54%. When the antacid is given 2 hours after rosuvastatin, no significant change in rosuvastatin plasma concentrations is observed.
Rosuvastatin; Ezetimibe: (Moderate) Coadministration of rosuvastatin with antacids has reduced rosuvastatin plasma concentrations by 54%. When the antacid is given 2 hours after rosuvastatin, no significant change in rosuvastatin plasma concentrations is observed. (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.
Sarecycline: (Major) Separate administration of sarecycline and antacids by 2 to 3 hours. Coadministration may impair absorption of sarecycline which may decrease its efficacy.
Scopolamine: (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.
Selpercatinib: (Major) Avoid coadministration of selpercatinib with antacids due to the risk of decreased selpercatinib exposure which may reduce its efficacy. If concomitant use is unavoidable, take selpercatinib 2 hours before or 2 hours after administration of antacids. Coadministration with acid-reducing agents decreases selpercatinib plasma concentrations.
Sodium Benzoate; Sodium Phenylacetate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
Sodium Citrate; Citric Acid: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage.
Sodium Ferric Gluconate Complex; ferric pyrophosphate citrate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.
Sodium Fluoride: (Moderate) Absorption of sodium fluoride may be reduced by concomitant use of antacids that contain aluminum. An interval of at least 2 hours is advisable between administration of sodium fluoride and aluminum hydroxide.
Sodium Phenylbutyrate; Taurursodiol: (Major) Avoid coadministration of aluminum-based antacids and taurursodiol, and consider other acid lowering medications. Coadministration may decrease the absorption of taurursodiol.
Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
Sodium Polystyrene Sulfonate: (Major) Simultaneous oral administration of cation-donating antacids or laxatives may reduce the potassium exchange capability of sodium polystyrene sulfonate. Examples of cation-donating antacids and laxatives include aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium citrate, and magnesium hydroxide. Patients who received concomitant oral sodium polystyrene sulfonate and non-absorbable cation-donating antacids and laxatives have developed systemic alkalosis. Intestinal obstruction due to concretions of aluminum hydroxide when used in combination with sodium polystyrene sulfonate has also been reported. One case of grand mal seizure has been reported in a patient with chronic hypocalcemia of renal failure who was given sodium polystyrene with magnesium hydroxide as laxative. Normally, antacids like magnesium hydroxide and calcium carbonate neutralize hydrochloric acid in the stomach, forming magnesium chloride and calcium chloride. As these compounds enter the small intestine, they react with bicarbonate, forming magnesium carbonate and calcium carbonate, which are insoluble. If polystyrene is administered, it blocks this reaction by binding to the magnesium and calcium ions before they can react with the bicarbonate. More hydrogen ions are lost from the stomach than are lost from the intestine, resulting in metabolic alkalosis. Rectal administration of sodium polystyrene sulfonate may reduce the severity of these interactions.
Sofosbuvir; Velpatasvir: (Moderate) Separate the use of antacids and velpatasvir administration by 4 hours. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy.
Sofosbuvir; Velpatasvir; Voxilaprevir: (Moderate) Separate the use of antacids and velpatasvir administration by 4 hours. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy.
Sotalol: (Moderate) Coadministration of antacids with sotalol reduces the Cmax and AUC of sotalol by 26% and 20%, respectively. This interaction results in a 25% reduction in the bradycardic effect of sotalol (measured at rest). Antacid administration two hours after the sotalol dose does not alter sotalol pharmacokinetics or pharmacodynamics. Instruct patients to avoid using antacids containing aluminum hydroxide or magnesium hydroxide within 2 hours of taking sotalol.
Sotorasib: (Moderate) Avoid coadministration of sotorasib and gastric-reducing agents, such as antacids. Coadministration may decrease sotorasib exposure resulting in decreased efficacy. If coadministration with antacids is necessary, administer sotorasib 4 hours before or 10 hours after an antacid.
Sparsentan: (Moderate) Administer sparsentan 2 hours before or after antacids. Simultaneous coadministration may decrease sparsentan exposure and efficacy. Medications that affect gastric pH may reduce sparsentan absorption.
Sucralfate: (Moderate) Antacids can interfere with the binding capacity of sucralfate to the GI mucosa, decreasing its effectiveness. Antacids should not be administered within 30 minutes of sucralfate. In addition, antacids or other aluminum-containing agents should be used cautiously with sucralfate in patients with chronic renal failure due to the aluminum content of sucralfate and the potential for aluminum toxicity.
Sumatriptan; Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.
Tacrolimus: (Major) Monitor tacrolimus whole blood trough concentration and reduce tacrolimus dose if needed during concurrent use of antacids. Magnesium and aluminum hydroxide antacids may increase the blood concentration of tacrolimus. In a single-dose crossover study in healthy volunteers, coadministration of tacrolimus and magnesium-aluminum-hydroxide resulted in a mean AUC increase of 21% and a 10% decrease in the mean tacrolimus Cmax, compared to tacrolimus administration alone.
Tetracycline: (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.
Thyroid hormones: (Moderate) To minimize an interaction, administer thyroid hormones at least 4 hours before or after antacids or other drugs containing aluminum hydroxide. Aluminum hydroxide, often found in antacids, interferes with the intestinal absorption of thyroid hormones. Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Tipranavir: (Moderate) Concurrent administration of tipranavir and ritonavir with antacids results in decreased tipranavir concentrations. Administer tipranavir and ritonavir 2 hours before or 1 hour after antacids.
Tramadol; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
Trihexyphenidyl: (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.
Trospium: (Moderate) Antacids may inhibit the oral absorption of antimuscarinics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.
Ursodeoxycholic Acid, Ursodiol: (Moderate) Aluminum hydroxide based antacids have been shown to adsorb bile acids in vitro and are expected to interfere with the efficacy of ursodeoxycholic acid, ursodiol. To minimize drug interactions, administer ursodiol at least 1 hour before or at least 2 hours after the aluminum-based antacid.
Valproic Acid, Divalproex Sodium: (Minor) Antacids containing the combination of magnesium and aluminum hydroxide have been shown to increase valproic acid AUC by an average of 12%. Although this finding is of marginal clinical significance, patients should be monitored for adverse effects in this situation while taking valproic acid and aluminum hydroxide.
Vincristine Liposomal: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
Both aluminum hydroxide and magnesium carbonate react with hydrochloric acid in the stomach. Aluminum hydroxide is slowly solubilized in the stomach and reacts with hydrochloric acid producing aluminum chloride and water. Magnesium carbonate reacts with hydrochloric acid to form magnesium chloride, water, and carbon dioxide. These chemical reactions neutralize gastric acid secretions and increase the gastric pH. The increases in gastric pH inhibit the proteolytic action of pepsin, an effect which is particularly important in patients with peptic ulcer disease. The increased pH and decreased pepsin production help in the healing of peptic ulcers. While gastric acids are neutralized, the actual secretion of acid is not effected. The chloride salts of aluminum and magnesium produced in the stomach react with bicarbonate in the small intestine to minimize the risk of systemic alkalosis. In addition, aluminum complexes to form the insoluble aluminum phosphate, which is excreted in the feces. This reduces the amount of phosphate that is available for absorption.
In the management of esophageal reflux, the increase in gastric pH produced by antacids, including aluminum hydroxide; magnesium carbonate, causes an increase in the lower esophageal sphincter pressure. This increased pressure minimizes the amount of reflux to the esophagus. Alginic acid, listed as an inactive ingredient in aluminum hydroxide; magnesium carbonate products is also purported to be useful in GERD. Alginic acid works by reacting with sodium bicarbonate and saliva to form a viscous solution of sodium alginate. This viscous solution floats on the surface of gastric contents so that when reflux occurs sodium alginate, rather than gastric contents, is refluxed and esophageal irritation is minimized. The antacid combination product should be administered with a full glass of water so that the sodium alginate can float on the water in the stomach. The presence of sodium alginate is only useful when the patient is in the upright position.
Pharmacokinetics:
Aluminum hydroxide; magnesium carbonate is administered orally.
Aluminum hydroxide reacts with hydrochloric acid in the stomach to produce aluminum chloride and water. About 17-30% of the aluminum chloride is absorbed and is rapidly excreted by the kidneys in patients with normal renal function. In the small intestine, aluminum chloride is rapidly converted to insoluble, poorly absorbed basic aluminum salts. Aluminum also combines with dietary phosphate in the intestine forming insoluble, nonabsorbable aluminum phosphate which is excreted in the feces. Magnesium carbonate reacts with hydrochloric acid in the stomach to form magnesium chloride, water, and carbon dioxide. Approximately 15-30% of the magnesium carbonate is absorbed and rapidly excreted by the kidneys in patients with normal renal function. The aluminum and magnesium that are not absorbed remain in the GI tract and are excreted in the feces.
-Special Populations
Renal Impairment
In patients with significant renal impairment, the amount of magnesium absorbed from aluminum hydroxide; magnesium carbonate products is significant enough to produce hypermagnesemia.