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Famotidine film-coated tablets on a matte clinical surface
DoseRoutine Famotidine — Famotidine film-coated tablets on a matte clinical surface. Original DoseRoutine photography.
medicationOTC supplementFamotidine is an approved medicine; the cited literature reports trial outcomes, not dosing advice.

FamotidineBenefits, Dosage & Interactions

Also known as: Pepcid

Famotidine is a medication classified as a histamine H2-receptor antagonist, often referred to as an H2 blocker. It works by decreasing the amount of acid produced in the stomach. It is typically taken in the evening. The reported plasma half-life is about 2.5 hours, which shapes dosing frequency.

How much Famotidine do people take?

Not stated here. The cited trials each used their own protocol amounts, and Famotidine is dosed by a prescriber or the approved product label — DoseRoutine records what you were told to take, it does not suggest an amount. Route reported: Oral (the route studied in the cited trials). Frequency reported: Set by the prescription or approved label, not by this record. These are amounts documented in the cited studies and labels for Famotidine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

See the full reported protocol and its sources

Researched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.

Evidence: Strong — 385 human randomized trials and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence

385 human randomized trials and regulatory approval on file.

Chemical structure of Famotidine (PubChem CID 5702160)
Structure via PubChem
Plasma half-life
2.5–3.5 h
Typical timing
in the evening
Default unit
mg

What published protocols report

Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.

Reported amounts
Not stated here. The cited trials each used their own protocol amounts, and Famotidine is dosed by a prescriber or the approved product label — DoseRoutine records what you were told to take, it does not suggest an amount.[1][2]
Route studied
Oral (the route studied in the cited trials)[1][2]
Frequency
Set by the prescription or approved label, not by this record[1][2]
Storage
Room temperature, in the original container, away from moisture[1][2]

Reported for Famotidine in the cited sources. Published ranges are not dosing advice.

References & evidence

Documents the Famotidine entry is written from. Each number matches an inline marker above.

  1. [1]Effect of Famotidine on Outcomes in Pulmonary Arterial Hypertension: A Randomized Controlled TrialLeary PJ, Rayner SG, Branch KRH, et al. · Chest · 2025 · Peer-reviewed · PMID 39761829
  2. [2]Effect of famotidine on hospitalized patients with COVID-19: A systematic review and meta-analysisChiu L, Shen M, Lo CH, et al. · PLoS One · 2021 · Peer-reviewed · PMID 34735523

References & Evidence

Sources on this page that document Famotidine dosing, timing and safety.

  1. [1]U.S. National Library of Medicine View source
  2. [2]National Center for Biotechnology Information View source

Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.

What is Famotidine?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.

Famotidine is a medication classified as a histamine H2-receptor antagonist, often referred to as an H2 blocker. It works by decreasing the amount of acid produced in the stomach. It is commonly used to treat and prevent various conditions involving excess stomach acid, including heartburn, acid indigestion, gastroesophageal reflux disease (GERD), and ulcers of the stomach and intestines. Famotidine can be obtained over-the-counter (OTC) in lower strengths for self-treatment of occasional heartburn, and in higher strengths by prescription from a healthcare provider for more serious or chronic conditions. It is available in various forms, including tablets and oral suspensions. According to DrugBank, Famotidine was developed by Yamanouchi Pharmaceutical Co. and was first approved for medical use in the United States in 1986. It is commonly known by its brand name, Pepcid.

What does the research say about Famotidine?

Tap a section to expand.

Famotidine acts as a competitive antagonist of histamine at the H2-receptors, primarily located on the parietal cells of the stomach lining. When histamine binds to these H2-receptors, it stimulates the parietal cells to produce and secrete gastric acid (hydrochloric acid). By blocking these receptors, famotidine prevents histamine from binding and thus reduces the activation of the proton pump, which is responsible for the final step of acid secretion. This action effectively decreases both the volume of gastric secretions and the concentration of hydrogen ions (acidity) in the stomach. This reduction in stomach acid helps alleviate symptoms associated with acid-related conditions and allows damaged esophageal or gastric tissue to heal. (DrugBank, PubChem)

Source for this section: Sources for How does Famotidine work?: Jumps to this entry in the sources and references list at the end of the page.

Famotidine offers several benefits related to the management of conditions caused by excessive stomach acid: * **Relief from Heartburn and Acid Indigestion:** Famotidine provides effective and relatively quick relief from symptoms of occasional heartburn and acid indigestion by reducing stomach acid output. * **Treatment of GERD:** For individuals with gastroesophageal reflux disease (GERD), famotidine helps manage symptoms like frequent heartburn, regurgitation, and difficulty swallowing by lowering stomach acid, which reduces irritation to the esophageal lining (MedlinePlus). * **Healing and Prevention of Ulcers:** It is used in the treatment and prevention of peptic ulcers (gastric and duodenal ulcers) by creating an environment conducive to healing of ulcerations and reducing the risk of recurrence (MedlinePlus). * **Treatment of Zollinger-Ellison Syndrome:** In conditions like Zollinger-Ellison syndrome, where the stomach produces abnormally high amounts of acid, famotidine can help control acid secretion and manage associated symptoms (MedlinePlus). * **Prevention of Stress Ulcers:** In some hospital settings, famotidine may be used to prevent stress ulcers in critically ill patients. These benefits stem directly from its ability to reduce stomach acid, thereby mitigating the irritating and damaging effects of acid on the gastrointestinal tract.

The efficacy of famotidine in treating acid-related conditions is well-established through clinical trials and extensive clinical use over several decades. For instance, a review of H2 receptor antagonists by the NIH Office of Dietary Supplements (ODS) and MedlinePlus confirms their effectiveness in managing peptic ulcers, GERD, and dyspepsia. Studies have shown famotidine to be effective in healing duodenal ulcers, with healing rates comparable to other H2 blockers but often with a more prolonged duration of action at similar dosages. For heartburn, trials comparing famotidine to placebo consistently demonstrate significant symptom relief. Its role in managing GERD is supported by its ability to reduce esophageal acid exposure. The FDA label for famotidine provides detailed information on its approved indications and clinical study data supporting its effectiveness. The Cochrane Library contains multiple reviews that often include famotidine as part of a class of drugs (H2-receptor antagonists) effective for various upper gastrointestinal disorders.

While generally well-tolerated, famotidine can cause side effects. Common side effects include: * Headache * Dizziness * Constipation or diarrhea * Nausea * Mild abdominal discomfort Less common but more serious side effects may include: * Allergic reactions (rash, itching/swelling, severe dizziness, trouble breathing) * Changes in heart rhythm (rare, more likely with intravenous administration in certain patients) * Liver problems (very rare) * Mental/mood changes (e.g., confusion, agitation, depression) - more commonly reported in elderly patients or those with kidney impairment. * Unusual tiredness or weakness Patients should seek immediate medical attention if they experience symptoms of a severe allergic reaction or severe side effects. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for What are the side effects of Famotidine?: Jumps to this entry in the sources and references list at the end of the page.

Before taking famotidine, inform your doctor or pharmacist if you are allergic to it or to other H2 blockers (e.g., cimetidine, ranitidine) or if you have any other allergies. Famotidine should be used with caution in individuals with kidney disease, as dose adjustments may be necessary due to its renal excretion. It should also be used cautiously in older adults, who may be more susceptible to side effects, particularly central nervous system effects like confusion. Individuals with difficulty swallowing or persistent abdominal pain, unexplained weight loss, or black/tarry stools should consult a healthcare professional before self-treating with OTC famotidine, as these symptoms could indicate a more serious condition. Pregnant or breastfeeding individuals should consult their doctor before using famotidine. (MedlinePlus, FDA label) This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for Who should avoid Famotidine?: Jumps to this entry in the sources and references list at the end of the page.

Famotidine is contraindicated in individuals with a known hypersensitivity to famotidine or other components of the formulation. While there are no absolute contraindications other than allergy to the drug itself, certain conditions warrant extreme caution or make its use inappropriate without careful medical supervision. These include severe kidney impairment, where dose reduction is often necessary. Patients with underlying undiagnosed gastrointestinal bleeding or obstruction should not use famotidine without a thorough medical evaluation, as it could mask symptoms of a more serious condition. (FDA label) This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for When should Famotidine not be taken?: Jumps to this entry in the sources and references list at the end of the page.

Famotidine can interact with certain medications, affecting their absorption or efficacy. Key interactions to be aware of include: * ** medicamentos that require stomach acid for absorption:** Famotidine reduces stomach acid, which can decrease the absorption of certain drugs, such as some azole antifungals (e.g., ketoconazole, itraconazole) and some HIV protease inhibitors (e.g., atazanavir). It is advisable to take these medications at a different time or consider alternative treatments if possible. * **Antacids:** While antacids can be used with famotidine for immediate relief, they should generally be taken at least 1-2 hours apart if used regularly, as they can sometimes interfere with famotidine's absorption. * **Dasatinib, Erlotinib, Pazopanib:** Famotidine can significantly reduce the absorption of these cancer medications, potentially leading to decreased effectiveness. Close monitoring or dose adjustments may be required, or alternative acid-reducing therapies considered. Always inform your healthcare provider about all prescription, over-the-counter, and herbal products you are taking. (MedlinePlus, DrugBank) This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.

Source for this section: Sources for What should you not mix with Famotidine?: Jumps to this entry in the sources and references list at the end of the page.

The typical timing for famotidine depends on the condition being treated and whether it is used over-the-counter or by prescription. For occasional heartburn, over-the-counter famotidine is typically taken as needed, often 10-60 minutes before eating food or drinking beverages that may cause heartburn. For therapeutic use, such as treating ulcers or GERD, it may be prescribed once or twice daily. A common regimen involves taking it at bedtime, as this can help control nocturnal acid production and reduce symptoms occurring overnight and in the morning. Famotidine can be taken with or without food. The specific dosage and timing must be set by a licensed clinician for prescription use.

Source for this section: Sources for When should you take Famotidine?: Jumps to this entry in the sources and references list at the end of the page.

Put it into practice

Reading about Famotidine is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.

What interacts with Famotidine?

Documented interactions for Famotidine: the other compound, the severity and confidence of the interaction, what happens, and what to do.
Interacts withSeverityTypeWhat happensWhat to do
Any supplement + medicationNoteCategory ruleConfidence: theoreticalSome supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page.Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.
Any vitamin + medicationNoteCategory ruleConfidence: theoreticalCertain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page.Specific pairs are checked against a licensed source; confirm with your provider.

Frequently asked questions about Famotidine

Famotidine typically starts to work within 15-60 minutes of taking an oral dose, and its acid-reducing effects can last for 10-12 hours, depending on the dosage. Peak effects are usually seen within 1-3 hours.

Yes, famotidine is the active ingredient in the brand-name medication Pepcid. Pepcid is a well-known brand, and famotidine is the generic form of the drug, offering the same therapeutic benefits.

For occasional heartburn, famotidine is usually taken as needed. However, for chronic conditions like GERD or ulcers, a healthcare provider may prescribe daily use. It's important to follow your doctor's instructions for daily use, as prolonged use without medical supervision could mask symptoms of serious underlying conditions.

Antacids (like Tums or Mylanta) work by neutralizing existing stomach acid and provide immediate, but short-lived, relief. Famotidine, an H2 blocker, works by reducing the production of stomach acid over a longer period. Famotidine takes longer to start working but offers more prolonged relief compared to antacids.

Famotidine can be used in children for certain acid-related conditions under the guidance of a healthcare professional. The dosage for children is based on weight and condition, and it should always be prescribed and monitored by a pediatrician or other qualified clinician.

Famotidine is a medication, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Because Famotidine is usually taken in the evening, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 2.5 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Famotidine with no sign-up.

Famotidine is typically taken in the evening. The reported plasma half-life is about 2.5 hours, which is what drives how often it is redosed. Ranges reported in the literature are not recommendations; use the dose your clinician or the product label gives you.

Combining a medication like Famotidine with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions

Each peptide class carries its own profile against Famotidine: a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.

A short plasma half-life of roughly 2.5 hours is why protocols often split Famotidine across the day rather than using a single dose. It is typically taken in the evening. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps

Because Famotidine clears quickly (plasma half-life around 2.5 hours), a missed dose leaves a real gap in exposure rather than being buffered by what is still in your system. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.

For Famotidine the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.

Not stated here. The cited trials each used their own protocol amounts, and Famotidine is dosed by a prescriber or the approved product label — DoseRoutine records what you were told to take, it does not suggest an amount. Route reported: Oral (the route studied in the cited trials). Frequency reported: Set by the prescription or approved label, not by this record. These are amounts documented in the cited studies and labels for Famotidine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

Which studies looked at Famotidine?

Peer-reviewed research indexed in PubMed. Each entry links to the original record.

  1. 1.Clinical pharmacokinetics of famotidine(opens PubMed in a new tab)Clin Pharmacokinet · 1991 · PMID 1764869 · https://pubmed.ncbi.nlm.nih.gov/1764869/

Sources cited on this page

Specific documents referenced by the numbered markers above. Each number matches the marker in the text.

  1. MedlinePlus(opens in a new tab)U.S. National Library of Medicine · medlineplus.gov/druginfo/meds/a687011.html
  2. PubChem CID 5702160(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/5702160

Verify at

Publisher search links for Famotidine. These are places to check the information — they are not citations, so they are not numbered.

DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.

What is the short answer on Famotidine?

Plain-text summary, safe to quote verbatim:

Famotidine is a medication classified as a histamine H2-receptor antagonist, often referred to as an H2 blocker. It works by decreasing the amount of acid produced in the stomach. It is typically taken in the evening. The reported plasma half-life is about 2.5 hours, which shapes dosing frequency.
Source: DoseRoutine — https://doseroutine.com/library/famotidine

Famotidine cheat sheet

DoseRoutine cheat sheet · Medication

Famotidine

Famotidine is a medication classified as a histamine H2-receptor antagonist, often referred to as an H2 blocker. It works by decreasing the amount of acid produced in the stomach.

Evidence

Strong

385 human randomized trials and regulatory approval on file.

Studied range

Not stated here. The cited trials each used their own protocol amounts, and Famotidine is dosed by a prescriber or the approved product label — DoseRoutine records what you were told to take, it does not suggest an amount.

Route

Oral (the route studied in the cited trials)

Frequency studied

Set by the prescription or approved label, not by this record

Half-life

2.5–3.5 h

Timing

in the evening

Storage

Room temperature, in the original container, away from moisture

OTC supplementFamotidine is an approved medicine; the cited literature reports trial outcomes, not dosing advice.

Key references

  1. Effect of Famotidine on Outcomes in Pulmonary Arterial Hypertension: A Randomized Controlled Trial (2025)
  2. Effect of famotidine on hospitalized patients with COVID-19: A systematic review and meta-analysis (2021)

Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/famotidine

Cite this page

Using this in an article, AI answer, or research note? Please attribute:

DoseRoutine. (2026). Famotidine — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/famotidine
Canonical URL

What compounds are similar to Famotidine?

Others in the medication category or studied for the same goals.

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