CriticalSystemic antimycotics. Imidazole derivatives×Alpha-adrenergic blockers for prostatic disorders
Updated · Methodology
Mechanism
Ketoconazole is a potent CYP3A4 inhibitor – the main tamsulosin metabolic route. Tamsulosin plasma levels rise 2- to 3-fold; orthostatic hypotension and syncope emerge.
Symptoms
Sudden blood pressure drop on standing, syncope, dizziness. Older patients: fall and fracture risk.
Management
The AEMPS label for tamsulosin says the drug must not be given with strong CYP3A4 inhibitors such as ketoconazole. Avoid the combination. Alternative antifungals: terbinafine for dermatophytosis or echinocandins for systemic mycoses. Alternative for benign prostatic hyperplasia: a 5α-reductase inhibitor (finasteride, dutasteride).
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: Ketoconazole tablet (Amerisyn LLC) – Prescribing Information (2014)– ; DailyMed setid 1d598696-c6f3-4b7c-ad73-949d2089df35
- AEMPS: Ficha técnica: Tamsulosina (nº registro 67308), sección 4.5 (2024)– AEMPS, CIMA, nº registro 67308, sección 4.5