CriticalClass III antiarrhythmics (Vaughan Williams)×Class Ia antiarrhythmic with antimuscarinic activity
Updated · Methodology
Mechanism
Amiodarone is the strongest clinical QT prolonger and CYP3A4 inhibitor. With disopyramide additive QT effect (each prolongs 30-50 ms).
Symptoms
QTc above 550 ms, syncope, torsades de pointes.
Management
Combination contraindicated. Choose one antiarrhythmic.
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
- DailyMed: Disopyramide: FDA prescribing information, Drug Interactions section (DailyMed) (2024)
- AEMPS: Ficha técnica: Amiodarona (nº registro 81291), sección 4.5 (2022)– AEMPS, CIMA, nº registro 81291, revisión 06/2022, sección 4.5