CriticalClass Ia antiarrhythmic with antimuscarinic activity×Macrolide antibiotic
Updated · Methodology
Mechanism
Erythromycin inhibits CYP3A4 (disopyramide metabolism) and itself prolongs QT. Dual torsades risk.
Symptoms
QTc above 500 ms, syncope, torsades de pointes within 3-7 days.
Management
Combination contraindicated. Alternative – azithromycin (no CYP3A4 inhibition or QT effect).
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 tecnica de Dicorynan (disopiramida) (2023)– AEMPS CIMA, 2023
- AEMPS: Ficha técnica: Eritromicina (nº registro 79380), sección 4.3 (2025)– AEMPS, CIMA, nº registro 79380, sección 4.3