Medically Reviewed on 2/17/2023

Generic Name: famotidine 

Brand Names: Pepcid, Pepcid AC, Acid Reducer, Heartburn Relief

Drug Class: Histamine H2 Antagonists, Gastrointestinal Agents, Other

What is famotidine, and what is it used for?

Famotidine is an oral drug that blocks the production of acid by acid-producing cells in the stomach. Since excessive stomach acid can damage the esophagus, stomach, and duodenum, and lead to inflammation and ulceration, reducing stomach acid prevents and heals acid-induced inflammation and ulcers.

Famotidine belongs to a class of drugs called H2 (histamine-2) blockers that also includes cimetidine (Tagamet), nizatidine (Axid), and ranitidine (Zantac). Histamine is a naturally-occurring chemical that stimulates cells in the stomach (parietal cells) to produce acid. 

Famotidine blocks the action of histamine on stomach cells and reduces the production of acid by the stomach.

  • Famotidine is useful in promoting the healing of stomach and duodenal ulcers and in reducing ulcer pain.
  • Famotidine has been effective in preventing recurrence of ulcers when given in low doses for prolonged periods of time.
  • Famotidine is also used for treating heartburn and in healing ulceration and inflammation of the esophagus (esophagitis) resulting from acid (gastroesophageal reflux disease or GERD).
  • High doses are used for treating conditions in which there are marked increases in acid secretion such as Zollinger-Ellison syndrome.
  • Over-the-counter preparations are used for treatment and prevention of occasional heartburn associated with acid indigestion (another name for GERD).

Famotidine was approved by the FDA in November 1986.

What are the side effects of famotidine?

Side effects of famotidine are rare. The most commonly reported minor side effects are:

Other important side effects include:

More serious side effects include:

What is the dosage for famotidine?

  • The recommended adult oral dose for treating duodenal ulcers is 40 mg once daily at bedtime or 20 mg twice daily. Most patients heal their ulcers within 4 weeks. The regimen for maintenance therapy after the ulcers are healed is 20 mg once a day at bedtime. The recommended oral dose for adults with gastric ulcers is, 40 mg once daily at bedtime.
  • Esophagitis is treated with 20 or 40 mg twice daily for up to 12 weeks. Zollinger-Ellison syndrome is treated with 20 mg every 6 hours, and doses up to 160 mg every 6 hours have been used in some patients.
  • GERD is treated with 20 mg twice daily for up to 6 weeks. Occasional heartburn is treated with 10-20 mg daily administered 15 to 60 minutes before ingestion of food or beverages that cause heartburn.

Which drugs interact with famotidine?


GERD is the back up of stomach acid into the esophagus. See Answer

Is famotidine safe to take if I'm pregnant or breastfeeding?

  • Use of famotidine during pregnancy has not been adequately evaluated.
  • Famotidine is secreted into breast milk. Due to the potential but unknown harm that famotidine might cause to the infant, nursing mothers should consider discontinuing famotidine.

What else should I know about famotidine?

What preparations of famotidine are available?

  • Tablets: 10, 20, and 40 mg.
  • Tablets (Chewable): 10 and 20 mg.
  • Suspension: 40 mg per 5 ml (teaspoon). Injection: 10 mg/ml.

How should I keep famotidine stored?

Tablets and suspension should be stored at room temperature, 15 C - 30 C (59 F - 86 F). Injection should be stored between 2 C - 8 C (36 F - 46 F).


Famotidine is a drug prescribed for the treatment of stomach and duodenal ulcers, heartburn, esophagitis, GERD, and Zollinger-Ellison syndrome. The most commonly reported minor side effects of famotidine are constipation, diarrhea, fatigue, headache, insomnia, muscle pain, nausea, and vomiting. Other important side effects include anemia, confusion, easy bruising or bleeding, hair loss, and rash. Consult with your doctor if pregnant or breastfeeding.

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See more info: famotidine on RxList
Medically Reviewed on 2/17/2023
Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


FDA Prescribing Information