CriticalTricyclic antidepressants (TCA)×Class III antiarrhythmic
Updated · Methodology
Mechanism
Amitriptyline (tricyclic antidepressant) prolongs QT. Dronedarone also prolongs QT. Additive effect raises ventricular arrhythmia risk. FDA Multaq Section 4.3 specifically lists QT-prolonging antidepressants as contraindications.
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. Replace the TCA with sertraline (minimal QT effect, up to 100 mg/day) or agomelatine. If a TCA is required, choose a non-QT antiarrhythmic (beta-blocker).
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: Amitriptilina (nº registro 89862), sección 4.5 (2026)– AEMPS, CIMA, nº registro 89862, revisión 05/2026, sección 4.5
- AEMPS: Ficha técnica: Dronedarona (nº registro 84320), sección 4.3 (2025)– AEMPS, CIMA, nº registro 84320, revisión 10/2025, sección 4.3