CriticalClass III antiarrhythmics (Vaughan Williams)×SSRI (selective serotonin reuptake inhibitor)
Updated · Methodology
Mechanism
Amiodarone is a class III antiarrhythmic, and its SmPC describes QT prolongation as a direct pharmacological effect of the drug. Class IA and III antiarrhythmics open the list of examples in both SSRI labels. The citalopram SmPC lists ongoing treatment with any drug capable of prolonging the QT interval among its contraindications, with no exceptions.
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 citalopram SmPC contraindications, so the question is which drug stays, not how far to cut the dose. Amiodarone washes out over weeks, so spacing the two drugs apart does not work: QT stays prolonged long after the last dose. Before any decision, potassium and magnesium are corrected and an ECG with QTc is recorded.
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
- AEMPS: Ficha técnica de Trangorex 200 mg (amiodarona) (2022)– AEMPS CIMA, nregistro 48048, revisión 08/2022, secciones 4.4 y 4.5
- AEMPS: Ficha técnica de Seropram 30 mg (citalopram) (2024)– AEMPS CIMA, nregistro 63564, revisión 01/2024, secciones 4.2, 4.3 y 4.4