famotidine
Brand names: Pepcid
Famotidine (Pepcid) reduces stomach acid. It is used to treat ulcers, heartburn, and acid reflux.
Drug Pricing (NADAC)
Generic Price
$0.10/unit
Generic Available
Yes (48 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine treats active duodenal ulcers and active gastric ulcers.
Common side effects
Headache, Dizziness, Constipation
Key warnings
In elderly patients and those with kidney problems, famotidine can cause confusion, delirium, or hallucinations.
How It Works
Famotidine is an H2 receptor antagonist. This means it blocks histamine, a substance that tells your stomach to make acid. By blocking histamine, famotidine reduces the amount of acid your stomach produces.
How to Take It
Take famotidine once a day before bedtime, or twice a day in the morning and before bedtime. You can take it with or without food. The usual dose for an active duodenal ulcer is 40 mg once daily or 20 mg twice daily. Your doctor will tell you how long to take it.
Pregnancy & Breastfeeding
It is not known if famotidine will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Famotidine may pass into breast milk, but it's not expected to harm the baby. Talk to your doctor about breastfeeding while taking this medicine.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time.
Storage
Store at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 57,983 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 110,018 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1995–2025.
Total Reports
110,018
Death-Related Reports
10,287
Hospitalization Reports
35,591
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | NAUSEA | 7,258 |
| 2 | FATIGUE | 6,866 |
| 3 | CHRONIC KIDNEY DISEASE | 6,644 |
| 4 | DIARRHOEA | 6,452 |
| 5 | DRUG INEFFECTIVE | 6,154 |
| 6 | OFF LABEL USE | 5,224 |
| 7 | DYSPNOEA | 5,202 |
| 8 | HEADACHE | 4,907 |
| 9 | ACUTE KIDNEY INJURY | 4,660 |
| 10 | PAIN | 4,619 |
| 11 | VOMITING | 4,464 |
| 12 | DIZZINESS | 4,226 |
| 13 | RENAL FAILURE | 4,104 |
| 14 | DEATH | 3,690 |
| 15 | PNEUMONIA | 3,504 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
In elderly patients and those with kidney problems, famotidine can cause confusion, delirium, or hallucinations. If you are elderly or have kidney problems, your doctor may prescribe a lower dose. Famotidine can hide the symptoms of stomach cancer. If your symptoms don't improve, tell your doctor.
Known Drug Interactions
albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without sulbactam methylprednisolone atenolol metronidazole azithromycin metoprolol caffeine, dietary ingestion nadolol cefaclor nifedipine co-trimoxazole (trimethoprim and sulfamethoxazole) nizatidine diltiazem norfloxacin dirithromycin ofloxacin enflurane omeprazole famotidine prednisone, prednisolone felodipine ranitidine finasteride rifabutin hydrocortisone roxithromycin isoflurane Sorbitol (purgative doses do not inhibit theophylline absorption) isoniazid sucralfate isradipine terbutaline, s...
Mechanism: Famotidine does not affect the amount of theophylline that stays in your blood.
What to do: These medicines are generally safe to use together.
( 7.1 ) • Tizanidine (CYP1A2) Substrate: Potential for substantial increases in blood concentrations of tizanidine resulting in hypotension, bradycardia or excessive drowsiness; avoid concomitant use, if possible. 7.2 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. Refer to the full prescribing information for tizanidine.
Mechanism: Famotidine can slow down the body's ability to clear tizanidine, which may lead to dangerously high levels of the drug in your blood.
What to do: Avoid taking these two drugs together if possible to prevent side effects like very low blood pressure or extreme drowsiness.
See the prescribing information for other drugs dependent on gastric pH for absorption for administration instructions, including atazanavir, erlotinib, ketoconazole, itraconazole, ledipasvir/sofosbuvir, nilotinib, and rilpivirine.
Mechanism: Famotidine reduces stomach acid, which can prevent ketoconazole from being absorbed into your system.
What to do: Your doctor may recommend taking these at different times or adjusting your treatment to ensure the medicine is absorbed.
See the prescribing information for other drugs dependent on gastric pH for absorption for administration instructions, including atazanavir, erlotinib, ketoconazole, itraconazole, ledipasvir/sofosbuvir, nilotinib, and rilpivirine.
Mechanism: Famotidine lowers stomach acid, which can make it harder for the body to absorb ledipasvir/sofosbuvir.
What to do: Ask your doctor for specific instructions on when to take these drugs to ensure they work correctly.
See the prescribing information for other drugs dependent on gastric pH for absorption for administration instructions, including atazanavir, erlotinib, ketoconazole, itraconazole, ledipasvir/sofosbuvir, nilotinib, and rilpivirine.
Mechanism: Famotidine reduces stomach acid, which is needed for the body to properly absorb itraconazole.
What to do: Consult your pharmacist or doctor for the best schedule to take these medications.
Common Questions
Can I take famotidine with other medications?
How long does it take for famotidine to work?
Can I drink alcohol while taking famotidine?
What should I do if I experience side effects?
Can I take famotidine long-term?
Is there a weight limit for children taking this medication?
What should I do if my heartburn comes back after stopping famotidine?
Can famotidine cause any serious side effects?
Does famotidine interact with any specific foods?
Can I crush or chew the tablet?
What are the common side effects of famotidine?
Does famotidine interact with other medications?
What drug class is famotidine?
Is famotidine safe during pregnancy?
Has famotidine been recalled?
Active Recalls
Microbial Contamination of Sterile Products; out of limit results obtained for endotoxin testing.
Fresenius Kabi USA, LLC
CGMP Deviations: product held outside appropriate storage temperature conditions.
Family Dollar Stores, Llc.
Related Medications in H2 Receptor Antagonist
Other drugs grouped near famotidine — same-class peers and common alternatives.
alosetron
Lotronex
Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS).
Compare with famotidine →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with famotidine →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with famotidine →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with famotidine →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with famotidine →
Medication Guides
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What the FDA Data Shows for famotidine
The FDA label for famotidine (sold under brand names such as Pepcid) classifies it as an over-the-counter product in the H2 Receptor Antagonist class. This medicine treats active duodenal ulcers and active gastric ulcers. Official labeling lists 4 commonly reported side effects, including Headache, Dizziness, Constipation.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 57,983 voluntary reports. The database also lists 11 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.10.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 2 recall records on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 22, 2025
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages