CriticalClass III antiarrhythmic×Systemic antimycotics. Imidazole derivatives
Updated · Methodology
Mechanism
Ketoconazole is a strong CYP3A4 inhibitor, the main dronedarone clearance route. Dronedarone plasma levels rise 17-fold. FDA Multaq Section 4.3 specifically lists strong CYP3A4 inhibitors.
Symptoms
QT prolongation on ECG. Clinically: dizziness, syncope, palpitations. Severe cases progress to polymorphic ventricular tachycardia (torsades de pointes) with risk of ventricular fibrillation and sudden cardiac death. Risk rises with hypokalaemia and hypomagnesaemia.
Management
The combination is not prescribed. Alternative antifungals: echinocandins (micafungin, caspofungin) or fluconazole for candidiasis (weaker CYP3A4 effect). Alternative antiarrhythmic: amiodarone or catheter ablation.
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: Multaq (dronedarone) prescribing information (2020)– ; DailyMed setid 7fa41601-7fb5-4155-8e50-2ae903f0d2d6
- AEMPS: Ficha técnica: Dronedarona (nº registro 84320), sección 4.3 (2025)– AEMPS, CIMA, nº registro 84320, revisión 10/2025, sección 4.3