MajorMacrolide antibiotic×Alpha-adrenergic blockers for prostatic disorders
Updated · Methodology
Mechanism
Clarithromycin blocks CYP3A4 – the main tamsulosin metabolic route. Tamsulosin plasma levels rise; orthostatic hypotension emerges.
Symptoms
Sudden blood pressure drop on standing, syncope, dizziness. Older patients: fall and fracture risk.
Management
During clarithromycin therapy, halve tamsulosin temporarily or use an alternative: finasteride/dutasteride (minimal CYP3A4 dependence). Alternative antibiotics: azithromycin or doxycycline.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Tamsulosin hydrochloride capsule (Rising Pharma Holdings, Inc.) – Prescribing Information (2014)– ; DailyMed setid a242c8dc-576e-4a1f-a9e7-a05d7ebc0e0a
- AEMPS: Ficha técnica: Tamsulosina (nº registro 67308), sección 4.5 (2024)– AEMPS, CIMA, nº registro 67308, sección 4.5