CriticalClass III antiarrhythmics (Vaughan Williams)×Class III antiarrhythmic
Updated · Methodology
Mechanism
Amiodarone and dronedarone are class III antiarrhythmics with overlapping mechanism and additive QT prolongation. Dronedarone was developed as a less toxic replacement for amiodarone, so combining them is not meaningful.
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. Choose one: amiodarone for high-risk atrial fibrillation with reduced ejection fraction, dronedarone for preserved ejection fraction without heart failure.
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 4.5 (2025)– AEMPS, CIMA, nº registro 84320, revisión 10/2025, sección 4.5