Amiodarone × Dronedarone

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.

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.

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.