Major
Amlodipine × Ketoconazole
Calcium channel blockers (dihydropyridines)×Systemic antimycotics. Imidazole derivatives
Mechanism
Ketoconazole is a strong CYP3A4 inhibitor – the main amlodipine metabolic route. Amlodipine plasma levels rise 2- to 3-fold; symptomatic hypotension and acute kidney injury risk.
Symptoms
Blood pressure drop: postural dizziness, syncope. Ankle oedema (typical of amlodipine), facial flushing, reflex tachycardia are possible.
Management
Avoid the combination. Alternative antifungals: terbinafine for dermatophytosis or echinocandins for systemic mycoses. If ketoconazole is needed, halve amlodipine.
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.