Skip to content
ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
H₂-Receptor Antagonist

Famotidine

Brand names: Pepcid, Antodine

Famotidine is a histamine H2-receptor antagonist used for acid-related dyspepsia, gastro-oesophageal reflux disease and peptic ulcer disease. It is generally less potent at suppressing acid than a proton pump inhibitor.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Indication Recommended Dosage ( 2.1 ) Adult and Pediatric Patients 40 kg and greater Active DU 40 mg once daily; or 20 mg twice daily Active Gastric Ulcer 40 mg once daily GERD 20 mg twice daily Erosive Esophagitis 20 mg twice daily; or 40 mg twice daily Adults Pathological Hypersecretory Conditions 20 mg every 6 hours; adjust to patient needs; maximum 160 mg every 6 hours Risk Reduction of DU Recurrence 20 mg once daily • See full prescribing information for complete dosing information, including dosing in renal impairment, and recommended treatment duration. ( 2.1 , 2.2 ) Administration ( 2.3 ): • Take once daily before bedtime or twice daily in the morning and before bedtime with or …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-10-22. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It competitively blocks histamine H2-receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion.

Prescribing in practice

  • Reduce the dose in renal impairment, as famotidine is largely renally cleared and can accumulate, with central nervous system effects such as confusion seen particularly in older or renally impaired patients.
  • It is generally well tolerated and, unlike older H2 antagonists, has few clinically important cytochrome P450 interactions.
  • As with proton pump inhibitors, acid suppression can mask the symptoms of gastric cancer, so investigate alarm features before long-term treatment.

Monitoring

No routine monitoring is required for most patients; review renal function where impairment is suspected and reassess the continued need for treatment periodically.

Counselling the patient

  • Tell your doctor if you have kidney problems, as the dose may need to be lowered.
  • Report new difficulty swallowing, weight loss or black stools, which need investigation.

Evidence & guidelines

Established therapy for acid-related disorders (NICE CG184).

Reference: NICE CG17 GORD; SPC Pepcid; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways