Dosing & Uses
Dosage Forms & Strengths
famotidine/calcium carbonate/magnesium hydroxide
chewable tablet
- 10mg/800mg/165mg
Heartburn/Indigestion
Chew 1 tablet completely, then swallow; do not exceed 2 tablets/24 hr
Dosage Forms & Strengths
famotidine/calcium carbonate/magnesium hydroxide
chewable tablet
- 10mg/800mg/165mg
Heartburn/Indigestion
<12 years
- Safety & efficacy not established
>12 years
- Chew 1 tablet completely, then swallow; do not exceed 2 tablets/24 hr
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (1)
- ceftriaxone
ceftriaxone, calcium carbonate. Other (see comment). Contraindicated. Comment: Do not use ANY calcium containing solutions (including Ringer or Harmann solutions) in combination with IV ceftriaxone; risk of potentially fatal particulate precipitation in lungs, kidneys. Separate by at least 48 hrs.
Serious - Use Alternative (41)
- atazanavir
calcium carbonate will decrease the level or effect of atazanavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Atazanavir solubility decreases as pH increases. Reduced plasma concentrations of atazanavir are expected if antacids or buffered medications are coadministered. Administer atazanavir 2 hr before or 1 hr after these medications.
famotidine will decrease the level or effect of atazanavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Atazanavir solubility decreases as pH increases. Substantially reduced plasma concentrations of atazanavir are expected if H2-receptor antagonists (H2RA) are coadministered. For treatment-naïve patients, take atazanavir simultaneously with the H2RA or at least 10 h afterwards. See dosage adjustment recommendations if coadministered in treatment-experienced patients. - baloxavir marboxil
magnesium hydroxide will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.
calcium carbonate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted. - bosutinib
famotidine will decrease the level or effect of bosutinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- demeclocycline
magnesium hydroxide decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- dapsone
famotidine will decrease the level or effect of dapsone by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
calcium carbonate will decrease the level or effect of dapsone by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. - dasatinib
calcium carbonate will decrease the level or effect of dasatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
famotidine will decrease the level or effect of dasatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. - demeclocycline
calcium carbonate, demeclocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.
- digoxin
famotidine will increase the level or effect of digoxin by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- digoxin
calcium carbonate will increase the level or effect of digoxin by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- doxycycline
magnesium hydroxide decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
calcium carbonate, doxycycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours. - eltrombopag
calcium carbonate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.
magnesium hydroxide decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours. - erdafitinib
calcium carbonate, erdafitinib. Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid coadministration during initial dosing adjustment period (ie, first 21 days). Increases in serum phosphate levels are a pharmacodynamic effect of FGFR inhibition. Serum phosphate binders may obscure decisions regarding initial dosage increase.
- infigratinib
magnesium hydroxide will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before and after administration of a locally-acting antacid.
- indinavir
famotidine will decrease the level or effect of indinavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
calcium carbonate will decrease the level or effect of indinavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. - infigratinib
calcium carbonate will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before and after administration of a locally-acting antacid.
famotidine will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before or 10 hr after administration of a H2-antagonist. - itraconazole
famotidine will decrease the level or effect of itraconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- ketoconazole
calcium carbonate will decrease the level or effect of ketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- ketoconazole
famotidine will decrease the level or effect of ketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- levoketoconazole
famotidine will decrease the level or effect of levoketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
calcium carbonate will decrease the level or effect of levoketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. - mefloquine
mefloquine increases toxicity of famotidine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.
- minocycline
magnesium hydroxide decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
calcium carbonate, minocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours. - neratinib
famotidine will decrease the level or effect of neratinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- oxytetracycline
magnesium hydroxide decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- nimodipine
calcium carbonate will increase the level or effect of nimodipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- nisoldipine
calcium carbonate will increase the level or effect of nisoldipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- nitrendipine
calcium carbonate will increase the level or effect of nitrendipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- oxytetracycline
calcium carbonate, oxytetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.
- pazopanib
famotidine will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; consider short-acting antacids in place of PPIs and H2 antagonists; separate antacid and pazopanib dosing by several hours
calcium carbonate will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; may use short-acting antacids in place of PPIs and H2 antagonists, but separate antacid and pazopanib dosing by several hours
magnesium hydroxide will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; may use short-acting antacids in place of PPIs and H2 antagonists, but separate antacid and pazopanib dosing by several hours - pexidartinib
famotidine will increase the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate pexidartinib by 2 hr before or 10 hr after taking an H2-antagonist.
- ponatinib
magnesium hydroxide decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- ponatinib
calcium carbonate decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- pimozide
famotidine, pimozide. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug.
pimozide, famotidine. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. - ponatinib
famotidine decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- potassium phosphates, IV
magnesium hydroxide decreases effects of potassium phosphates, IV by cation binding in GI tract. Avoid or Use Alternate Drug. Magnesium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.
- pretomanid
pretomanid will increase the level or effect of famotidine by Other (see comment). Avoid or Use Alternate Drug. In vitro studies demonstrated that pretomanid significantly inhibits OAT3; monitor for increased adverse effects and consider dosage reduction for OAT3 substrates.
- raltegravir
magnesium hydroxide will decrease the level or effect of raltegravir by cation binding in GI tract. Avoid or Use Alternate Drug. Magnesium containing antacids reduce raltegravir plasma levels when taken within 6 hr of raltegravir dose
- risedronate
famotidine will increase the level or effect of risedronate by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Applies only to delayed release formulation; accelerates pH-sensitive dissolution of delayed release risedronate
- secretin
famotidine, secretin. Other (see comment). Avoid or Use Alternate Drug. Comment: Concomitant use of H2-receptor antagonists may cause a hyperresponse in gastrin secretion in response to stimulation testing with secretin, falsely suggesting gastrinoma. Discontinue H2-receptor antagonists at least 2 days before administering secretin to aid in the diagnosis of gastrinoma.
- sotorasib
magnesium hydroxide will decrease the level or effect of sotorasib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid.
famotidine will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid.
calcium carbonate will decrease the level or effect of sotorasib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid. - sparsentan
famotidine decreases effects of sparsentan by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. H2-antagonists may decrease sparsentan exposure which may reduce efficacy of sparsentan.
- tetracycline
magnesium hydroxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
Monitor Closely (171)
- acalabrutinib
famotidine decreases levels of acalabrutinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Acalabrutinib solubility decreases with increasing gastric pH. Administer acalabrutinib 2 hr before an H2-receptor antagonist.
calcium carbonate decreases levels of acalabrutinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Acalabrutinib solubility decreases with increasing gastric pH. Separate dosing by at least 2 hr between administration of antacids and acalabrutinib. - acebutolol
calcium carbonate decreases effects of acebutolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of acebutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - bictegravir
magnesium hydroxide will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir can be taken under fasting conditions 2 hr before antacids containing Al, Mg, or Ca. Routine administration of bictegravir simultaneously with, or 2 hr after, antacids containing Al, Mg, or Ca is not recommended.
- budesonide
famotidine decreases effects of budesonide by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Enteric-coated budesonide dissolves at pH >5.5. Also, dissolution of extended-release budesonide tablets is pH dependent. Coadministration with drugs that increase gastric pH may cause these budesonide products to prematurely dissolve, and possibly affect release properties and absorption of the drug in the duodenum.
- alendronate
calcium carbonate decreases levels of alendronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- allopurinol
calcium carbonate decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- amantadine
calcium carbonate will increase the level or effect of amantadine by Other (see comment). Modify Therapy/Monitor Closely. Urine pH changes towards alkalinic conditions may lead to an accumulation of amantadine with a possible increase in adverse reactions. Monitor for adverse reactions of amantadine.
- amlodipine
calcium carbonate decreases effects of amlodipine by pharmacodynamic antagonism. Use Caution/Monitor.
- atenolol
calcium carbonate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - azithromycin
calcium carbonate decreases levels of azithromycin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- bearberry
calcium carbonate will increase the level or effect of bearberry by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- benazepril
calcium carbonate decreases effects of benazepril by unspecified interaction mechanism. Use Caution/Monitor.
- benzphetamine
calcium carbonate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- betaxolol
calcium carbonate decreases effects of betaxolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of betaxolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - bictegravir
calcium carbonate will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir can be taken under fasting conditions 2 hr before antacids containing calcium. However, bictegravir and supplements containing calcium can be taken together with food. Routine administration of bictegravir (under fasting conditions) simultaneously with, or 2 hr after, calcium supplements or antacids containing calcium is not recommended.
- bisoprolol
calcium carbonate decreases effects of bisoprolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of bisoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - bosutinib
calcium carbonate decreases levels of bosutinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Bosutinib displays pH-dependent solubility; may use short-acting antacids with administration separated by 2 hr.
- budesonide
calcium carbonate decreases effects of budesonide by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Enteric-coated budesonide dissolves at pH >5.5. Also, dissolution of extended-release budesonide tablets is pH dependent. Coadministration with drugs that increase gastric pH may cause these budesonide products to prematurely dissolve, and possibly affect release properties and absorption of the drug in the duodenum.
- cabotegravir
magnesium hydroxide will decrease the level or effect of cabotegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer antacid products at least 2 hr before or 4 hr after taking oral cabotegravir.
calcium carbonate will decrease the level or effect of cabotegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer antacid products at least 2 hr before or 4 hr after taking oral cabotegravir. - captopril
calcium carbonate decreases effects of captopril by unspecified interaction mechanism. Use Caution/Monitor. Calcium carbonate may decrease absorption of captopril.
- chloroquine
magnesium hydroxide will decrease the level or effect of chloroquine by Mechanism: inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate doses by at least 4 hr
- carbonyl iron
famotidine will decrease the level or effect of carbonyl iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of carbonyl iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - carvedilol
calcium carbonate decreases effects of carvedilol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of carvedilol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - cefdinir
famotidine will decrease the level or effect of cefdinir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- cefdinir
calcium carbonate will decrease the level or effect of cefdinir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- cefditoren
famotidine will decrease the level or effect of cefditoren by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of cefditoren by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - cefpodoxime
famotidine will decrease the level or effect of cefpodoxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of cefpodoxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - cefuroxime
famotidine will decrease the level or effect of cefuroxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of cefuroxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - celecoxib
calcium carbonate decreases levels of celecoxib by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- ciprofloxacin
magnesium hydroxide decreases levels of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Coadministration of ciprofloxacin with multivalent cation-containing products may reduce the bioavailability of ciprofloxacin by 90%. Administer ciprofloxacin at least 2 hours before or 6 hours after using these products. Use alternatives if available.
- crizotinib
magnesium hydroxide decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. .
famotidine decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. . - celiprolol
calcium carbonate decreases effects of celiprolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - deferiprone
magnesium hydroxide decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.
- chenodiol
calcium carbonate decreases levels of chenodiol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- chloroquine
calcium carbonate will decrease the level or effect of chloroquine by cation binding in GI tract. Use Caution/Monitor. Separate doses by at least 4 hr
- ciprofloxacin
calcium carbonate decreases effects of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Ciprofloxacin should be administered 2 hr before or 6 hr after calcium salts.
- clevidipine
calcium carbonate decreases effects of clevidipine by pharmacodynamic antagonism. Use Caution/Monitor.
- crizotinib
calcium carbonate decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. .
- cyclosporine
calcium carbonate decreases levels of cyclosporine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
famotidine will increase the level or effect of cyclosporine by unknown mechanism. Use Caution/Monitor. Delayed resorption of cyclosporine has been reported when famotidine is coadministered with cyclosporine. - dabrafenib
famotidine will decrease the level or effect of dabrafenib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that alter upper GI tract pH (eg, PPIs, H2-blockers, antacids) may decrease dabrafenib solubility and reduce its bioavailability
calcium carbonate will decrease the level or effect of dabrafenib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that alter upper GI tract pH (eg, PPIs, H2-blockers, antacids) may decrease dabrafenib solubility and reduce its bioavailability - deferiprone
calcium carbonate decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.
- deflazacort
magnesium hydroxide and deflazacort both decrease serum potassium. Use Caution/Monitor.
- dexmethylphenidate
famotidine will increase the level or effect of dexmethylphenidate by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Applies only to extended release formulation
- deferoxamine
deferoxamine decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Deferoxamine chelates iron; its affinity for other minerals is unknown.
- delafloxacin
calcium carbonate will decrease the level or effect of delafloxacin by cation binding in GI tract. Modify Therapy/Monitor Closely. Oral delafloxacin form chelates with alkaline earth and transition metal cations. Administer oral delafloxacin at least 2 hr before or 6 hr after these agents.
- dextroamphetamine
calcium carbonate will increase the level or effect of dextroamphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- digoxin
calcium carbonate increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor.
- diltiazem
calcium carbonate decreases effects of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor.
- dolutegravir
magnesium hydroxide will decrease the level or effect of dolutegravir by cation binding in GI tract. Use Caution/Monitor. Administer dolutegravir 2 hr before or 6 hr after taking medications containing polyvalent cations; use alternative therapy if available
calcium carbonate will decrease the level or effect of dolutegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer dolutegravir 2 hr (dolutegravir or abacavir/dolutegravir/lamivudine) or 4 hr (dolutegravir/rilpivirine) before or 6 hr after taking medications containing polyvalent cations. - elvitegravir
calcium carbonate will decrease the level or effect of elvitegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Elvitegravir plasma concentrations are lower with antacids due to the formation of ionic complexes in the GI tract and not due to changes in gastric pH; separate dose from antacid by at least 2 hr
- fleroxacin
magnesium hydroxide decreases levels of fleroxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
calcium carbonate decreases levels of elvitegravir/cobicistat/emtricitabine/tenofovir DF by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration from antacids by 2 hr.
- enalapril
calcium carbonate decreases effects of enalapril by unspecified interaction mechanism. Use Caution/Monitor.
- ephedrine
calcium carbonate will increase the level or effect of ephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- erdafitinib
famotidine increases levels of erdafitinib by decreasing renal clearance. Modify Therapy/Monitor Closely. Consider alternatives that are not OCT2 substrates or consider reducing the dose of OCT2 substrates based on tolerability.
- erlotinib
famotidine decreases levels of erlotinib by Other (see comment). Use Caution/Monitor. Comment: Avoid combination when possible. If concurrent use is required erlotinib should be taken 10 hours after a H2-antagonist and at least 2 hours before the next dose of H2-antagonist.
- erythromycin base
calcium carbonate increases levels of erythromycin base by unknown mechanism. Use Caution/Monitor.
- erythromycin ethylsuccinate
calcium carbonate increases levels of erythromycin ethylsuccinate by unknown mechanism. Use Caution/Monitor.
- erythromycin lactobionate
calcium carbonate increases levels of erythromycin lactobionate by unknown mechanism. Use Caution/Monitor.
- erythromycin stearate
calcium carbonate increases levels of erythromycin stearate by unknown mechanism. Use Caution/Monitor.
- esmolol
calcium carbonate decreases effects of esmolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of esmolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - estramustine
calcium carbonate decreases levels of estramustine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Patients should take estramustine with water at least 1h before or 2h after meals.
- etidronate
calcium carbonate decreases levels of etidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- felodipine
calcium carbonate decreases effects of felodipine by pharmacodynamic antagonism. Use Caution/Monitor.
- ferric maltol
calcium carbonate will decrease the level or effect of ferric maltol by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
famotidine will decrease the level or effect of ferric maltol by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - ferrous fumarate
calcium carbonate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
famotidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - ferrous gluconate
famotidine will decrease the level or effect of ferrous gluconate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of ferrous gluconate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - ferrous sulfate
famotidine will decrease the level or effect of ferrous sulfate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- flecainide
calcium carbonate will increase the level or effect of flecainide by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- fosamprenavir
famotidine will decrease the level or effect of fosamprenavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of fosamprenavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - fosinopril
calcium carbonate decreases effects of fosinopril by unspecified interaction mechanism. Use Caution/Monitor.
- gefitinib
famotidine decreases levels of gefitinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Separate gefitinib and H2-antagonist doses by at least 6 hr.
- gabapentin
calcium carbonate decreases levels of gabapentin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- gabapentin enacarbil
calcium carbonate decreases levels of gabapentin enacarbil by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- gefitinib
calcium carbonate decreases levels of gefitinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Separate gefitinib and antacid doses by at least 6 hr.
- gemifloxacin
magnesium hydroxide decreases levels of gemifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
calcium carbonate, gemifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - glipizide
famotidine will increase the level or effect of glipizide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will increase the level or effect of glipizide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - lanthanum carbonate
lanthanum carbonate, magnesium hydroxide. cation binding in GI tract. Use Caution/Monitor. Administer antacid at least 2 hours before or after lanthanum. .
- glyburide
famotidine will increase the level or effect of glyburide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will increase the level or effect of glyburide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - ibandronate
calcium carbonate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- iron dextran complex
famotidine will decrease the level or effect of iron dextran complex by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- imidapril
calcium carbonate decreases effects of imidapril by unspecified interaction mechanism. Use Caution/Monitor.
- iron dextran complex
calcium carbonate will decrease the level or effect of iron dextran complex by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- iron sucrose
famotidine will decrease the level or effect of iron sucrose by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of iron sucrose by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - isoniazid
calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- ledipasvir/sofosbuvir
famotidine decreases levels of ledipasvir/sofosbuvir by Other (see comment). Use Caution/Monitor. Comment: Ledipasvir solubility decreases as pH increases; drugs that increase gastric pH are expected to decrease levels of ledipasvir; H2-receptor antagonists may be administered simultaneously with or 12 hr apart from ledipasvir/sofosbuvir at a dose that does not exceed doses comparable to famotidine 40 mg BID.
- isradipine
calcium carbonate decreases effects of isradipine by pharmacodynamic antagonism. Use Caution/Monitor.
- itraconazole
calcium carbonate will decrease the level or effect of itraconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Administer acid neutralizing medicines at least 2 hours before or 2 hours after itraconazole.
- ketoconazole
calcium carbonate decreases levels of ketoconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- labetalol
calcium carbonate decreases effects of labetalol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of labetalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - lactulose
calcium carbonate decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.
- lanthanum carbonate
lanthanum carbonate, calcium carbonate. cation binding in GI tract. Use Caution/Monitor. Administer antacid at least 2 hours before or after lanthanum. .
- ledipasvir/sofosbuvir
calcium carbonate decreases levels of ledipasvir/sofosbuvir by Other (see comment). Use Caution/Monitor. Comment: Ledipasvir solubility decreases as pH increases; drugs that increase gastric pH are expected to decrease levels of ledipasvir; separate antacid and ledipasivr/sofosbuvir administration by 4 hr.
- levofloxacin
magnesium hydroxide decreases levels of levofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
calcium carbonate, levofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - levoketoconazole
calcium carbonate decreases levels of levoketoconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- moxifloxacin
magnesium hydroxide decreases levels of moxifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- levothyroxine
calcium carbonate decreases levels of levothyroxine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- lisdexamfetamine
calcium carbonate will increase the level or effect of lisdexamfetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- lisinopril
calcium carbonate decreases effects of lisinopril by unspecified interaction mechanism. Use Caution/Monitor.
- memantine
calcium carbonate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- mesalamine
famotidine will decrease the level or effect of mesalamine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely.
- methscopolamine
calcium carbonate decreases levels of methscopolamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- methylphenidate
famotidine decreases effects of methylphenidate by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Since the characteristics of methylphenidate extended release capsules (Ritalin LA) are pH dependent, coadministration of antacids or acid suppressants could alter the release of methylphenidate. Consider separating the administration of the antacid and the methylphenidate extended-release capsules may be avoided.
calcium carbonate decreases effects of methylphenidate by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Since the characteristics of methylphenidate extended release capsules (Ritalin LA) are pH dependent, coadministration of antacids or acid suppressants could alter the release of methylphenidate. Consider separating the administration of the antacid and the methylphenidate extended-release capsules may be avoided.
famotidine will increase the level or effect of methylphenidate by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Applies only to extended release formulation - metoprolol
calcium carbonate decreases effects of metoprolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of metoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - mifepristone
famotidine, mifepristone. Either increases toxicity of the other by QTc interval. Use Caution/Monitor.
mifepristone, famotidine. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. - mexiletine
calcium carbonate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- moexipril
calcium carbonate decreases effects of moexipril by unspecified interaction mechanism. Use Caution/Monitor.
- moxifloxacin
calcium carbonate, moxifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- mycophenolate
calcium carbonate will decrease the level or effect of mycophenolate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
famotidine will decrease the level or effect of mycophenolate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - nadolol
calcium carbonate decreases effects of nadolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of nadolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - nelfinavir
famotidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- nebivolol
calcium carbonate decreases effects of nebivolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of nebivolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - neratinib
calcium carbonate will decrease the level or effect of neratinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate antacid and neratinib dosing by 3 hr.
- nicardipine
calcium carbonate decreases effects of nicardipine by pharmacodynamic antagonism. Use Caution/Monitor.
- nifedipine
calcium carbonate decreases effects of nifedipine by pharmacodynamic antagonism. Use Caution/Monitor.
- nilotinib
famotidine decreases levels of nilotinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Avoid this interaction by administering H2 antagonists 10 hr after or 2 hr before nilotinib.
calcium carbonate decreases levels of nilotinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Avoid this interaction by administering antacids 2 hr after or 2 hr before nilotinib. - nisoldipine
calcium carbonate decreases effects of nisoldipine by pharmacodynamic antagonism. Use Caution/Monitor.
- ofloxacin
magnesium hydroxide decreases levels of ofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- omadacycline
magnesium hydroxide will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- pancrelipase
magnesium hydroxide decreases effects of pancrelipase by pharmacodynamic antagonism. Use Caution/Monitor. Antacids may negate beneficial effects of enzymes.
- penicillamine
magnesium hydroxide decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- pexidartinib
magnesium hydroxide will decrease the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate pexidartinib by 2 hr before or after taking a locally-acting antacid.
- polysaccharide iron
famotidine will decrease the level or effect of polysaccharide iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- nitrofurantoin
calcium carbonate decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- ofloxacin
calcium carbonate, ofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- omadacycline
calcium carbonate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- pamidronate
calcium carbonate decreases levels of pamidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- pancrelipase
calcium carbonate decreases effects of pancrelipase by pharmacodynamic antagonism. Use Caution/Monitor. Antacids may negate beneficial effects of enzymes.
- penbutolol
calcium carbonate decreases effects of penbutolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of penbutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - penicillamine
calcium carbonate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- perindopril
calcium carbonate decreases effects of perindopril by unspecified interaction mechanism. Use Caution/Monitor.
- pexidartinib
calcium carbonate will decrease the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate pexidartinib by 2 hr before or after taking a locally-acting antacid.
- pindolol
calcium carbonate decreases effects of pindolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of pindolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - polysaccharide iron
calcium carbonate will decrease the level or effect of polysaccharide iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- posaconazole
famotidine will decrease the level or effect of posaconazole by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of posaconazole by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - potassium phosphates, IV
calcium carbonate decreases effects of potassium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.
- rilpivirine
famotidine will decrease the level or effect of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Concurrent use, may cause treatment failure and/or the development of rilpivirine or NNRTI resistance owing to decreased levels. Administer H2 antagonists at least 12 hours before or at least 4 hours after rilpivirine.
- propranolol
calcium carbonate decreases effects of propranolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of propranolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - quinapril
calcium carbonate decreases effects of quinapril by unspecified interaction mechanism. Use Caution/Monitor.
- quinidine
calcium carbonate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.
- ramipril
calcium carbonate decreases effects of ramipril by unspecified interaction mechanism. Use Caution/Monitor.
- rifampin
calcium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids
- rilpivirine
calcium carbonate decreases levels of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Coadministration of antacids with rilpivirine may cause significant decreases in rilpivirine plasma concentrations because of increased gastric pH. If antacids must be administered, they should be given at least 2 hr before or at least 4 hr after rilpivirine. For the combination product dolutegravir/rilpivirine, antacids should be given at least 4 hr before or at least 6 hr afterwards.
- riociguat
magnesium hydroxide decreases levels of riociguat by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration by at least 1 hour.
calcium carbonate decreases levels of riociguat by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration by at least 1 hour. - risedronate
calcium carbonate decreases levels of risedronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- sarecycline
magnesium hydroxide will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- rose hips
famotidine will decrease the level or effect of rose hips by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
calcium carbonate will decrease the level or effect of rose hips by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - rosuvastatin
calcium carbonate decreases levels of rosuvastatin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- saquinavir
famotidine will increase the level or effect of saquinavir by unspecified interaction mechanism. Use Caution/Monitor.
- sarecycline
calcium carbonate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- serdexmethylphenidate/dexmethylphenidate
famotidine will increase the level or effect of serdexmethylphenidate/dexmethylphenidate by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Applies only to extended release formulation
- sodium phosphates, IV
calcium carbonate decreases effects of sodium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.
magnesium hydroxide decreases effects of sodium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Magnesium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available. - sodium sulfate/?magnesium sulfate/potassium chloride
sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
- vismodegib
magnesium hydroxide will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown
- sodium sulfate/potassium sulfate/magnesium sulfate
sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
- sofosbuvir/velpatasvir
calcium carbonate will decrease the level or effect of sofosbuvir/velpatasvir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Velpatasvir solubility decreases as gastric pH increases (practically insoluble at pH >5). Separate administration of sofosbuvir/velpatasvir from antacids by at least 4 hr.
famotidine will decrease the level or effect of sofosbuvir/velpatasvir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Velpatasvir solubility decreases as gastric pH increases (practically insoluble at pH >5). H2 receptor antagonists may be administered simultaneously with or 12 hr apart from sofosbuvir/velpatasvir at a dose that does not exceed doses comparable to famotidine 40 mg BID. - sotalol
calcium carbonate decreases effects of sotalol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of sotalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - tolbutamide
famotidine will increase the level or effect of tolbutamide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- sparsentan
calcium carbonate decreases effects of sparsentan by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Administer sparsentan 2 hours before or after administration of antacids. Antacids may decrease sparsentan exposure which may reduce efficacy of sparsentan.
- squill
calcium carbonate increases toxicity of squill by unspecified interaction mechanism. Use Caution/Monitor.
- strontium ranelate
calcium carbonate decreases levels of strontium ranelate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Applies to oral form of calcium. Separate by 2 hr.
- tiludronate
calcium carbonate decreases levels of tiludronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
- timolol
calcium carbonate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of timolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours. - tolbutamide
calcium carbonate will increase the level or effect of tolbutamide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- trandolapril
calcium carbonate decreases effects of trandolapril by unspecified interaction mechanism. Use Caution/Monitor.
- ursodiol
calcium carbonate decreases effects of ursodiol by pharmacodynamic antagonism. Use Caution/Monitor.
- varenicline
famotidine will increase the level or effect of varenicline by decreasing renal clearance. Use Caution/Monitor.
- verapamil
calcium carbonate decreases effects of verapamil by pharmacodynamic antagonism. Use Caution/Monitor.
- vismodegib
calcium carbonate will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown
famotidine will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown - vitamin D
vitamin D, calcium carbonate. Other (see comment). Use Caution/Monitor. Comment: The concurrent use of vitamin D with calcium salts is generally beneficial; in some patients this combination may result in hypercalcemia.
vitamin D increases levels of magnesium hydroxide by Other (see comment). Use Caution/Monitor. Comment: Vitamin D can increase serum magnesium concentrations, particularly in the presence of renal impairment. The combined use of vitamin D and magnesium-containing products should be avoided, if possible, in patients with chronic renal failure. - zoledronic acid
calcium carbonate decreases levels of zoledronic acid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.
Minor (84)
- alendronate
famotidine increases levels of alendronate by unspecified interaction mechanism. Minor/Significance Unknown. Monitor for increase in alendronate side effects.
- amikacin
amikacin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
amikacin decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown. - amiloride
amiloride decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
amiloride increases levels of magnesium hydroxide by decreasing renal clearance. Minor/Significance Unknown. - amphotericin B deoxycholate
amphotericin B deoxycholate decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- aripiprazole
famotidine decreases levels of aripiprazole by unspecified interaction mechanism. Minor/Significance Unknown.
- aspirin
calcium carbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- aspirin rectal
calcium carbonate, aspirin rectal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- aspirin/citric acid/sodium bicarbonate
calcium carbonate, aspirin/citric acid/sodium bicarbonate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- axitinib
famotidine will decrease the level or effect of axitinib by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown.
- balsalazide
calcium carbonate, balsalazide. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- bazedoxifene/conjugated estrogens
bazedoxifene/conjugated estrogens decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- bendroflumethiazide
bendroflumethiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
bendroflumethiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown. - blessed thistle
blessed thistle decreases effects of famotidine by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction.
blessed thistle decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction. - bumetanide
bumetanide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- budesonide
budesonide decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- calcitonin salmon
calcitonin salmon increases levels of magnesium hydroxide by decreasing renal clearance. Minor/Significance Unknown.
- ceftibuten
famotidine will decrease the level or effect of ceftibuten by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown.
- bumetanide
bumetanide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
- caffeine
caffeine decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
- calcitriol topical
calcitriol topical increases levels of calcium carbonate by pharmacodynamic synergism. Minor/Significance Unknown. Topical calcitriol may lead to hypercalcemia.
- carbonyl iron
calcium carbonate decreases levels of carbonyl iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
carbonyl iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - chlorothiazide
chlorothiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
chlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia. - chlorthalidone
chlorthalidone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
chlorthalidone decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown. - choline magnesium trisalicylate
calcium carbonate, choline magnesium trisalicylate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- conjugated estrogens
conjugated estrogens decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- chromium
calcium carbonate decreases levels of chromium by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.
- conjugated estrogens, vaginal
conjugated estrogens, vaginal decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- cortisone
cortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- cyanocobalamin
famotidine decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- cyclopenthiazide
cyclopenthiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
cyclopenthiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia. - deflazacort
deflazacort decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- dextrose
dextrose decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- devil's claw
devil's claw decreases effects of famotidine by pharmacodynamic antagonism. Minor/Significance Unknown.
devil's claw decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown. - dexamethasone
dexamethasone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- dextrose (Antidote)
dextrose (Antidote) decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- digoxin
digoxin decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- doxercalciferol
doxercalciferol increases levels of magnesium hydroxide by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- drospirenone
drospirenone increases levels of magnesium hydroxide by decreasing renal clearance. Minor/Significance Unknown.
- estradiol
estradiol decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- estrogens conjugated synthetic
estrogens conjugated synthetic decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- estrogens esterified
estrogens esterified decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- estropipate
estropipate decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- ethacrynic acid
ethacrynic acid decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- furosemide
furosemide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- gentamicin
gentamicin decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- glucagon intranasal
glucagon intranasal increases levels of magnesium hydroxide by decreasing renal clearance. Minor/Significance Unknown.
- hydrochlorothiazide
hydrochlorothiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- ibandronate
magnesium hydroxide decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- indapamide
indapamide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- isavuconazonium sulfate
isavuconazonium sulfate will increase the level or effect of famotidine by Other (see comment). Minor/Significance Unknown. Isavuconazonium sulfate, an OCT2 inhibitor, may increase the effects or levels of OCT2 substrates.
- diflunisal
calcium carbonate, diflunisal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- drospirenone
drospirenone decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
- ethacrynic acid
ethacrynic acid decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
- ferric maltol
ferric maltol increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
calcium carbonate decreases levels of ferric maltol by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - ferrous fumarate
calcium carbonate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - ferrous gluconate
ferrous gluconate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
calcium carbonate decreases levels of ferrous gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - ferrous sulfate
ferrous sulfate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- fludrocortisone
fludrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- furosemide
furosemide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.
- gentamicin
gentamicin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- hydrochlorothiazide
hydrochlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
- hydrocortisone
hydrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- indapamide
indapamide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
- iron dextran complex
calcium carbonate decreases levels of iron dextran complex by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
iron dextran complex increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - iron sucrose
calcium carbonate decreases levels of iron sucrose by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
iron sucrose increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - isoniazid
isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- isotretinoin
isotretinoin increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- lily of the valley
calcium carbonate increases effects of lily of the valley by unspecified interaction mechanism. Minor/Significance Unknown.
- manganese
calcium carbonate, manganese. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.
- mannitol
mannitol decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- mesalamine
calcium carbonate, mesalamine. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).
- mestranol
mestranol decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.
- metformin
famotidine increases levels of metformin by decreasing renal clearance. Minor/Significance Unknown.
- methyclothiazide
methyclothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
methyclothiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown. - methylprednisolone
methylprednisolone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.
- metolazone
metolazone decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- metolazone
metolazone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.
- neomycin PO
neomycin PO decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
neomycin PO decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown. - nitrofurantoin
magnesium hydroxide decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- paromomycin
paromomycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- paromomycin
paromomycin decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.
- phytoestrogens
famotidine decreases levels of phytoestrogens by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- polysaccharide iron
calcium carbonate decreases levels of polysaccharide iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
polysaccharide iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - sodium polystyrene sulfonate
sodium polystyrene sulfonate increases levels of magnesium hydroxide by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis.
Adverse Effects
Frequency Not Defined
Headache
Constipation
Diarrhea
Warnings
Contraindications
Hypersensitivity
Other H2 antagonists or components of the formulation
Renal impairment (OTC)
Pain whe swallowing food, vomiting with blood, or bloody or black stools (OTC)
Caution
Severe renal or hepatic impairment
If patient taking a prescription drug, the patient should ask a doctor or a pharmacist whether acid reducers can be taken concomitantly with it
Patients with kidney disease should ask doctor before use
Prolonged QT intervals reported in patients with renal impairment; torsades de pointes reported
Relief of symptoms does not preclude presence of gastric malignancy
Use caution in renal impairment (moderate to severe); dosage adjustment recommended
In pediatric patients increased risk for development of acute gastroentiritis and community-acquired pneumonia reported
Some dosage forms may contain benzyl alcohol and/or sodium benzoate/benzoid acid, which has been associated with gasping syndrome in neonates
Pregnancy & Lactation
Pregnancy category: B
Lactation: American Academy of Pediatrics classifies as compatible with breast feeding
Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Famotidine is an H2-antagonist
Calcium carbonate & magnesium hydroxide are antacids
