CriticalClass III antiarrhythmic×Selective serotonin reuptake inhibitors (SSRIs)
Updated · Methodology
Mechanism
Dronedarone is a class III antiarrhythmic. Its SmPC describes a QTc increase of about 10 ms as its own effect and separately contraindicates torsade-inducing drugs alongside it. The escitalopram SmPC contraindicates any QT-prolonging drug alongside it: the ban is written broadly, and the classes in brackets are examples.
Symptoms
QTc prolongation on ECG, palpitations, dizziness, syncope. The end point is polymorphic ventricular tachycardia of the torsade type progressing to ventricular fibrillation. The risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, decompensated heart failure and in women.
Management
The pair sits in the escitalopram SmPC contraindications, so the question is which drug stays, not how far to cut the dose. The ban runs both ways: the dronedarone label contraindicates torsade-inducing drugs, the SSRI label contraindicates QT-prolonging ones. Before either drug starts, potassium, magnesium and QTc are checked.
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: Lexapro (escitalopram) prescribing information (2023)– FDA label, Allergan, Inc., DailyMed setid 13bb8267-1cab-43e5-acae-55a4d957630a, revised 10/2023, sections 4, 5.2 and 7
- AEMPS: Ficha técnica de Multaq 400 mg (dronedarona) (2025)– AEMPS CIMA, nregistro 09591003, secciones 4.3 y 4.4
- AEMPS: Ficha técnica de Cipralex 10 mg (escitalopram) (2026)– AEMPS CIMA, nregistro 65230, revisión 03/2026, secciones 4.3 y 4.5