Famotidine interactions

Famotidine (Pepcid), an H2 blocker has 60 documented interactions across the FDA labels and fact sheets we index: 12 major, 28 moderate, 10 minor, and 10 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.

Interactions from the label

Major interactions (12)

  • • Gastric Acid Reducing Agents: Avoid co-administration with proton pump inhibitors (PPIs). (Acalabrutinib label, Drug interactions)

  • AlcoholAlcoholMajor

    Serious and fatal adverse reactions have been reported in low-birth weight and preterm neonates who received benzyl-alcohol-containing drugs intravenously. (Famotidine label, Warnings and precautions)

  • CimetidineH2 blockerMajor

    Famotidine Injection is contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis) to famotidine or other H 2 -receptor antagonists. (Famotidine label, Contraindications)

  • Dichlorphenamidecarbonic anhydrase inhibitorMajor

    Use of KEVEYIS with drugs that are sensitive to OAT1 inhibition (e.g., methotrexate, famotidine, oseltamivir) is not recommended [see Clinical Pharmacology (12.3) ]. (Dichlorphenamide label, Drug interactions)

  • Use of RPV with proton pump inhibitors is contraindicated and use of RPV with H 2 -receptor antagonists requires staggered administration [see Contraindications (4) and Clinical Pharmacology (12.3) ] . (Emtricitabine, rilpivirine, and tenofovir label, Drug interactions)

  • Famotidine Injection is contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis) to famotidine or other H 2 -receptor antagonists. (Famotidine label, Contraindications)

  • MethylphenidateCNS stimulantMajor

    Intervention Concomitant use of methylphenidate extended-release orally disintegrating tablets with a gastric pH modulator (i.e., a H2-blocker or a proton pump inhibitor) is not recommended. (Methylphenidate label, Drug interactions)

  • NizatidineH2 blockerMajor

    Famotidine Injection is contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis) to famotidine or other H 2 -receptor antagonists. (Famotidine label, Contraindications)

  • Concomitant Use With Gastric Acid-Reducing Agents : Avoid concomitant use of VOTRIENT with gastric acid-reducing agents. (Pazopanib label, Drug interactions)

  • RanitidineH2 blockerMajor

    Famotidine Injection is contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis) to famotidine or other H 2 -receptor antagonists. (Famotidine label, Contraindications)

  • RisedronatebisphosphonateMajor

    Concomitant administration of Risedronate sodium delayed-release and H 2 blockers or PPIs is not recommended. (Risedronate label, Drug interactions)

  • Tizanidinemuscle relaxantMajor

    Tizanidine (CYP1A2) Substrate : Potential for substantial increases in blood concentrations of tizanidine resulting in hypotension, bradycardia or excessive drowsiness; avoid concomitant use, if possible. (Famotidine label, Drug interactions)

Moderate interactions (28)

  • AtazanavirantiretroviralModerate

    An H2RA dose comparable to famotidine 20 mg once daily up to a dose comparable to famotidine 40 mg twice daily can be used with REYATAZ 300 mg with ritonavir 100 mg in treatment-naive patients. (Atazanavir label, Drug interactions)

  • BosutinibModerate

    Proton Pump Inhibitors (PPI) As an alternative to PPIs, use short-acting antacids or H2 blockers and separate dosing by more than 2 hours from BOSULIF dosing. (Bosutinib label, Drug interactions)

  • Cannabidiol (prescription)anticonvulsantModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • CefpodoximecephalosporinModerate

    Drug Interactions Antacids Concomitant administration of high doses of antacids (sodium bicarbonate and aluminum hydroxide) or H 2 blockers reduces peak plasma levels by 24% to 42% and the extent of absorption by 27% to 32%, respectively. (Cefpodoxime label, Drug interactions)

  • CiprofloxacinfluoroquinoloneModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • Deferasiroxiron supplementModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • ErlotinibModerate

    Drugs the Increase Gastric pH Co-administration of erlotinib with proton pump inhibitors (e.g., omeprazole) and H-2 receptor antagonists (e.g., ranitidine) decreased erlotinib exposure [see Clinical Pharmacology (12.3) ]. (Erlotinib label, Drug interactions)

  • FluvoxamineSSRIModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • FosamprenavirantiretroviralModerate

    Histamine H 2 -receptor antagonists: Cimetidine, famotidine, nizatidine, ranitidine a Fosamprenavir calcium: ↓ Amprenavir Fosamprenavir calcium/ritonavir: Interaction not evaluated Use with caution. (Fosamprenavir label, Drug interactions)

  • FosphenytoinanticonvulsantModerate

    …Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazole, sulfadiazine, sulfamethoxazole-trimethoprim Other Acute alcohol intake, amiodarone,… (Fosphenytoin label, Drug interactions)

  • GefitinibModerate

    Drugs Affecting Gastric pH Drugs that elevate gastric pH (e.g., proton pump inhibitors, histamine H 2 -receptor antagonists, and antacids) may reduce plasma concentrations of gefitinib. (Gefitinib label, Drug interactions)

  • GlimepiridesulfonylureaModerate

    …glimepiride, increasing the susceptibility to and/or intensity of hypoglycemia: oral anti-diabetic medications, pramlintide acetate, insulin, angiotensin converting enzyme (ACE) inhibitors, H 2 receptor antagonists, fibrates, propoxyphene, pentoxifylline, somatostatin analogs, anabolic steroids and androgens, cyclophosphamide, phenyramidol, guanethidine, fluconazole, sulfinpyrazone,… (Glimepiride label, Drug interactions)

  • GlipizidesulfonylureaModerate

    …angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, propoxyphene, salicylates, somatostatin analogs (e.g., octreotide), sulfonamide antibiotics, nonsteroidal anti-inflammatory agents, chloramphenicol, probenecid, coumarins, voriconazole, H2 receptor antagonists, and quinolones. (Glipizide label, Drug interactions)

  • IbandronatebisphosphonateModerate

    H2 Blockers In healthy volunteers, co-administration with ranitidine resulted in a 20% increased bioavailability of ibandronate, which was not considered to be clinically relevant (see CLINICAL PHARMACOLOGY [12.3] ) . (Ibandronate label, Drug interactions)

  • Itraconazoleazole antifungalModerate

    Gastrointestinal Drugs Drugs that reduce gastric acidity e.g. acid neutralizing medicines such as aluminum hydroxide, or acid secretion suppressors such as H 2 - receptor antagonists and proton pump inhibitors (e.g., omeprazole). (Itraconazole label, Drug interactions)

  • Ketoconazoleazole antifungalModerate

    Drugs that may decrease ketoconazole plasma concentrations Drugs that reduce the gastric acidity (e.g., acid neutralizing medicines such as aluminum hydroxide, or acid secretion suppressors such as H 2 -receptor antagonists and proton pump inhibitors) impair the absorption of ketoconazole from ketoconazole tablets. (Ketoconazole label, Drug interactions)

  • Ledipasvir and sofosbuvirantiviralModerate

    Concomitant Drug Class: Drug Name Effect on Concentration ↓ = decrease, ↑ = increase Clinical Comment tenofovir DF = tenofovir disoproxil fumarate Acid Reducing Agents: ↓ ledipasvir Ledipasvir solubility decreases as pH increases. (Ledipasvir and sofosbuvir label, Drug interactions)

  • MexiletineantiarrhythmicModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • Anaphylactic Shock and Hypersensitivity Reactions: Premedicate all patients with a combination of an H1-antihistamine, an H2 blocker, and a leukotriene inhibitor prior to each APHEXDA dose. (Motixafortide label, Warnings and precautions)

  • OctreotideModerate

    Proton Pump Inhibitors, H2-receptor Antagonists, or Antacids: may decrease bioavailability of MYCAPSSA and the MYCAPSSA dose may need to be increased (‎ 7 ). (Octreotide label, Drug interactions)

  • PhenytoinanticonvulsantModerate

    …Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazole, sulfadiazine, sulfamethoxazole-trimethoprim Other Acute alcohol intake, amiodarone,… (Phenytoin label, Drug interactions)

  • Pioglitazone and glimepiridethiazolidinedioneModerate

    …tablets, increasing the susceptibility to and/or intensity of hypoglycemia: oral anti-diabetic medications, pramlintide acetate, insulin, angiotensin converting enzyme (ACE) inhibitors, H2 receptor antagonists, fibrates, propoxyphene, pentoxifylline, somatostatin analogs, anabolic steroids and androgens, cyclophosphamide, phenyramidol, guanethidine, fluconazole, sulfinpyrazone,… (Pioglitazone and glimepiride label, Drug interactions)

  • RilpivirineantiretroviralModerate

    H 2 -Receptor Antagonists: cimetidine famotidine nizatidine ranitidine ↔ rilpivirine (famotidine taken 12 hours before rilpivirine or 4 hours after rilpivirine) The combination of EDURANT or EDURANT PED and H 2 -receptor antagonists should be used with caution as coadministration may cause significant decreases in rilpivirine plasma concentrations (increase in… (Rilpivirine label, Drug interactions)

  • Clinical Effect/Recommendation Acid Reducing Agents: ↓ velpatasvir Velpatasvir solubility decreases as pH increases. (Sofosbuvir and velpatasvir label, Drug interactions)

  • TemsirolimusModerate

    …physician, treatment may be resumed with the administration of an H 1 -receptor antagonist (such as diphenhydramine), if not previously administered [see Dosage and Administration (2.2) ] , and/or an H 2 -receptor antagonist (such as intravenous famotidine 20 mg or intravenous ranitidine 50 mg) approximately 30 minutes before restarting the TORISEL infusion. (Temsirolimus label, Warnings and precautions)

  • Viloxazinenorepinephrine reuptake inhibitorModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

  • WarfarinanticoagulantModerate

    …tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil,… (Warfarin label, Drug interactions)

  • ZileutonCYP1A2 inhibitorModerate

    Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. (Famotidine label, Drug interactions)

Minor mentions (10)

  • CefaclorcephalosporinMinor

    Drug Interactions Antacids The extent of absorption of cefaclor extended-release tablets is diminished if magnesium or aluminum hydroxide-containing antacids are taken within 1 hour of administration; H 2 blockers do not alter either the rate or the extent of absorption of cefaclor extended-release tablets. (Cefaclor label, Drug interactions)

  • CidofovirantiviralMinor

    …Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine). (Cidofovir label, Drug interactions)

  • Darunavir and cobicistatantiretroviralMinor

    …drug-drug interactions have not been observed or are not anticipated with concomitant use of darunavir and cobicistat with rilpivirine, dolutegravir, raltegravir, abacavir, emtricitabine, emtricitabine/tenofovir alafenamide, tenofovir DF, lamivudine, stavudine, zidovudine, or acid modifying medications (antacids, H 2 -receptor antagonists, proton pump inhibitors). (Darunavir and cobicistat label, Drug interactions)

  • IronVitamin and mineralMinor

    Acid-reducing medicines lower stomach acid and can reduce the amount of iron absorbed from supplements and food. (NIH Office of Dietary Supplements, Iron)

  • LapatinibP-glycoprotein inhibitorMinor

    Acid-Reducing Agents The aqueous solubility of lapatinib is pH dependent, with higher pH resulting in lower solubility. (Lapatinib label, Drug interactions)

  • MidazolambenzodiazepineMinor

    No change in choice reaction time or sedation index was detected after dosing with the H2 receptor antagonists. (Midazolam label, Drug interactions)

  • MoexiprilACE inhibitorMinor

    Moexipril hydrochloride has been used in clinical trials concomitantly with calcium-channel-blocking agents, diuretics, H 2 blockers, digoxin, oral hypoglycemic agents, and cholesterol-lowering agents. (Moexipril label, Drug interactions)

  • Nisoldipinedihydropyridine calcium channel blockerMinor

    No pharmacodynamic effects of either histamine H 2 receptor antagonist were observed. (Nisoldipine label, Drug interactions)

  • Prasugrelantiplatelet agentMinor

    Effient can be administered with aspirin (75 mg to 325 mg per day), heparin, GPIIb/IIIa inhibitors, statins, digoxin, and drugs that elevate gastric pH, including proton pump inhibitors and H 2 blockers [see Clinical Pharmacology (12.3) ] . (Prasugrel label, Drug interactions)

  • Vitamin B12Vitamin and mineralMinor

    Long-term acid-reducing therapy interferes with B12 absorption from food and can lead to deficiency. (NIH Office of Dietary Supplements, Vitamin B12)

No significant interaction reported (10)

  • Alvimopanopioid antagonistNo interaction

    Effects of Concomitant Acid Blockers or Antibiotics A population pharmacokinetic analysis suggests that the pharmacokinetics of alvimopan were not affected by concomitant administration of acid blockers (proton pump inhibitors (PPIs), histamine-2 (H 2 ) receptor antagonists) or antibiotics. (Alvimopan label, Drug interactions)

  • AminophyllinemethylxanthineNo interaction

    …ampicillin, with or without sulbactam atenolol azithromycin caffeine, dietary ingestion cefaclor co-trimoxazole (trimethoprim and sulfamethoxazole) diltiazem dirithromycin enflurane famotidine felodipine finasteride hydrocortisone isoflurane isoniazid isradipine influenza vaccine ketoconazole lomefloxacin mebendazole medroxyprogesterone methylprednisolone metronidazole… (Aminophylline label, Drug interactions)

  • AripiprazoleantipsychoticNo interaction

    Drugs Having No Clinically Important Interactions with ABILIFY MAINTENA Based on pharmacokinetic studies with oral aripiprazole, no dosage adjustment of ABILIFY MAINTENA is required when administered concomitantly with famotidine, valproate, lithium, lorazepam [see Clinical Pharmacology (12.3) ] . (Aripiprazole label, Drug interactions)

  • DesloratadineantihistamineNo interaction

    …safety profile of desloratadine. [See Clinical Pharmacology (12.3) .] 7.3 Cimetidine In controlled clinical studies co-administration of desloratadine with cimetidine, a histamine H2-receptor antagonist, resulted in increased plasma concentrations of desloratadine and 3 hydroxydesloratadine, but there were no clinically relevant changes in the safety profile… (Desloratadine label, Drug interactions)

  • EfavirenzantiretroviralNo interaction

    …Significant Interactions with Efavirenz No dosage adjustment is recommended when efavirenz is given with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, lorazepam, nelfinavir, nucleoside reverse transcriptase inhibitors (abacavir, emtricitabine, lamivudine, stavudine, tenofovir disoproxil fumarate, zidovudine),… (Efavirenz label, Drug interactions)

  • Efavirenz, lamivudine, and tenofovirantiretroviralNo interaction

    Drugs without Clinically Significant Interactions No dosage adjustment is recommended when SYMFI is administered with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, and lorazepam. (Efavirenz, lamivudine, and tenofovir label, Drug interactions)

  • …GENVOYA Based on drug interaction studies conducted with the components of GENVOYA, no clinically significant drug interactions have been observed or are expected when GENVOYA is combined with the following drugs: famciclovir, famotidine, ledipasvir, methadone, omeprazole, prasugrel (active metabolite), sertraline, sofosbuvir, velpatasvir, and voxilaprevir. (Elvitegravir, cobicistat, emtricitabine, and tenofovir label, Drug interactions)

  • LenacapavirantiretroviralNo interaction

    …triazolam is concomitantly administered with SUNLENCA 7.4 Drugs without Clinically Significant Interactions with SUNLENCA Based on drug interaction studies conducted with SUNLENCA, no clinically significant drug interactions have been observed with: darunavir/cobicistat, cobicistat, famotidine, pitavastatin, rosuvastatin, tenofovir alafenamide, and voriconazole. (Lenacapavir label, Drug interactions)

  • Posaconazoleazole antifungalNo interaction

    No clinically relevant effects on the pharmacokinetics of Noxafil delayed-release tablets were observed during concomitant use with antacids, H 2 -receptor antagonists and proton pump inhibitors, and metoclopramide [see Clinical Pharmacology (12.3) ] . (Posaconazole label, Drug interactions)

  • TheophyllinemethylxanthineNo interaction

    …nifedipine cefaclor nizatidine co-trimoxazole (trimethoprim and sulfamethoxazole) norfloxacin ofloxacin diltiazem omeprazole dirithromycin prednisone, prednisolone enflurane ranitidine famotidine rifabutin felodipine roxithromycin finasteride Sorbitol (purgative doses do not inhibit hydrocortisone theophylline absorption) isoflurane sucralfate isoniazid terbutaline,… (Theophylline label, Drug interactions)

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Not medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.