Formulary
Famotidine: Indications, Dosing, Side Effects and Interactions
Famotidine clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 3 min read
Famotidine: Indications, Dosing, Side Effects and Interactions
Famotidine clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Treatment of benign gastric and duodenal ulceration**
- **Adult** (By Mouth): 40 mg once daily for 4-8 weeks, dose to be taken at night.
**Maintenance treatment of duodenal ulceration**
- **Adult** (By Mouth): 20 mg once daily, dose to be taken at night.
**Reflux oesophagitis**
- **Adult** (By Mouth): 20-40 mg twice daily for 6-12 weeks; maintenance 20 mg twice daily.
Cautions
For all h2-receptor antagonists Signs and symptoms of gastric cancer Cautions, further information Gastric cancer H 2 -receptor antagonists might mask symptoms of gastric cancer; particular care is required in patients presenting with 'alarm features' in such cases gastric malignancy should be ruled out before treatment.
Side effects
For all h2-receptor antagonists Common or very common Diarrhoea; dizziness; fatigue; headache; myalgia; skin reactions Uncommon Confusion; depression; erectile dysfunction; gynaecomastia; hallucination; hepatitis; leucopenia; nausea Rare or very rare Agranulocytosis; alopecia; arthralgia; atrioventricular block; fever; pancytopenia; thrombocytopenia Side-effects For famotidine Common or very common Constipation Uncommon Appetite decreased; dry mouth; taste altered; vomiting Rare or very rare Anxiety; chest tightness; drowsiness; insomnia; interstitial pneumonia; jaundice cholestatic; libido decreased; muscle cramps; neutropenia; paraesthesia; psychiatric disorder; seizures; severe cutaneous adverse reactions (SCARs)
Interactions
**Severe interactions:**
- Indocyanine green as an index of hepatic blood flow and/or hepatic drug extraction has been tested and no significant effects have been found.
**Other interactions (18):**
- Famotidine does not interact with the cytochrome P450-linked drug metabolizing enzyme system.
- Compounds metabolized by this system which have been tested in man have included warfarin, theophylline, phenytoin, diazepam, propranolol, aminopyrine and antipyrine.
- Studies in patients stabilized on phenprocoumon therapy have shown no pharmacokinetic interaction with famotidine and no effect on the pharmacokinetic or anticoagulant activity of phenprocoumon.
- In addition, studies with famotidine have shown no augmentation of expected blood alcohol levels resulting from alcohol ingestion.
- The absorption of ketoconazole and itraconazole could be reduced.
- Ketoconazole should be given 2 hours before famotidine administration.
Pregnancy
Manufacturer advises avoid unless potential benefit outweighs risk.
Breast feeding
Present in milk-not known to be harmful but manufacturer advises avoid.
Renal impairment
Use with caution. M Dose adjustments Use half of normal dose if creatinine clearance less than 30 mL/minute. Consider reducing dose to 20 mg once daily at night if creatinine clearance less than 10 mL/minute. M See Prescribing in renal impairment .
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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