famotidine: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
famotidine: clinical details
Prescribing considerations
- Exclude gastric malignancy before treating a gastric ulcer; symptom improvement does not rule it out.
- Review renal function because famotidine is predominantly renally eliminated and can accumulate in renal impairment.
- Safety and efficacy have not been established in children for the selected product.
- Review medicines whose absorption depends on gastric acidity, particularly certain antiretrovirals, antifungals and tyrosine kinase inhibitors.
Contraindications and cautions
- Hypersensitivity to famotidine or any product excipient.
- Previous hypersensitivity to another H2-receptor antagonist because cross-sensitivity has been reported.
Monitoring
- Renal function where impairment is present or suspected.
- Blood count and liver function during prolonged high-exposure treatment.
- Clinical response and alarm features in ulcer or reflux disease.
- Neurological effects and QT-related risk if famotidine may accumulate in renal impairment.
Clinical pharmacology
Famotidine competitively blocks gastric H2 receptors, suppressing basal and stimulated acid and pepsin secretion. It is rapidly absorbed, has low plasma-protein binding and is excreted mainly unchanged in urine, with limited hepatic conversion to an inactive sulfoxide metabolite.
Formulation and product differences
- The selected product is a brown, round, film-coated tablet scored for easier swallowing rather than equal division.
- Appearance, excipients and score-line function can differ between manufacturers; check the specific product information when allergy or swallowing issues matter.
famotidine preparations and strengths
Tablet
Route: Oral
Strengths: 20 mg, 40 mg
famotidine interactions
By raising stomach pH or affecting absorption and elimination, famotidine can alter some medicines' exposure or effectiveness.
Atazanavir
Reduced stomach acidity may lower its absorption and effectiveness.
Ketoconazole and itraconazole
Famotidine may reduce absorption of these antifungals; ask a pharmacist about administration timing.
Posaconazole oral suspension
Absorption may be reduced, so combined use should be avoided where possible.
Dasatinib, erlotinib, gefitinib and pazopanib
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.