Famotidine
PEPCID
What it isH2 receptor antagonist; GERD and ulcer disease.
Why this oneUnlike cimetidine, it has essentially no CYP inhibition, making it the H2 blocker for polypharmacy and on-demand use.
What limits itTolerance erodes scheduled acid suppression within weeks. Reduce in renal impairment; accumulation can cause confusion or QT effects.
FDA-approved for
- GERD/ulcers (1986)
Off-label
- adjunct in anaphylaxis and urticaria
- stress ulcer prophylaxis
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Active duodenal ulcer | Adults & peds ≥40 kg | 40 mg QD or 20 mg BID | 40 mg QD or 20 mg BID | |
| Active gastric ulcer | Adults & peds ≥40 kg | 40 mg QD | 40 mg QD | |
| Symptomatic nonerosive GERD | Adults & peds ≥40 kg | 20 mg BID | 20 mg BID | |
| Erosive esophagitis | Adults & peds ≥40 kg | 20 mg BID or 40 mg BID | 20 mg BID or 40 mg BID | |
| Pathological hypersecretory conditions | Adults | 20 mg q6h | adjust to patient needs | 160 mg q6h |
| Reduction of risk of DU recurrence | Adults | 20 mg QD | 20 mg QD |
Renal Reduce dosage for moderate–severe impairment (CrCl <60); no adjustment for mild (CrCl ≥60)
Hepatic Undefined
Instructions
- Take once daily before bedtime or twice daily (morning and before bedtime)
- May be taken with or without food; may be given with antacids
- For pediatric patients <40 kg, use another formulation (oral suspension or lower-dose tablet)
Contraindications
- Serious hypersensitivity (e.g., anaphylaxis) to famotidine or other H2-receptor antagonists
Cautions
- CNS adverse reactions (confusion, delirium, seizures) in elderly and moderate/severe renal impairment — reduce dose
- Absence of GI symptoms does not preclude gastric malignancy — evaluate before/after treatment
Adverse reactions
- Headache
- Dizziness
- Constipation
- Diarrhea
Pregnancy Insufficient data to establish drug-associated risk; animal studies showed no adverse developmental effects
Lactation Limited data; present in human milk with no reported effects on breastfed infant
NO BOXED WARNINGS
Principal riskDose adjustment needed in renal impairment
Cost, est. cash$4–$80/month
Generic entry2001
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityLong-term infection, magnesium/B12 and bone risks; selected agents have clinically important CYP interactions.
Mechanism of action: Famotidine ballicule
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