MajorClass III antiarrhythmic×Other antidepressants (NaSSA)
Updated · Methodology
Mechanism
Mirtazapine prolongs QT dose-dependently (especially above 30 mg/day). Combined with dronedarone, torsades de pointes risk rises.
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Severe cases: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia and hypomagnesaemia.
Management
The combination is acceptable at low mirtazapine doses (≤30 mg/day) and normal potassium. ECG before start and at 2 weeks. Alternative antidepressants with minimal QT effect: agomelatine or sertraline (up to 100 mg).
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Sources
- FDA: Multaq (dronedarone) prescribing information (2020)– ; DailyMed setid 7fa41601-7fb5-4155-8e50-2ae903f0d2d6
- AEMPS: Ficha técnica: Mirtazapina Cinfa 30 mg (nº registro 67068), secciones 4.5 y 4.7 (2026)– AEMPS, CIMA, nº registro 67068, revisión 06/2026, secciones 4.5 y 4.7