MajorClass Ic antiarrhythmic×Class Ia antiarrhythmic (sodium channel blocker with intermediate kinetics)
Updated · Methodology
Mechanism
Quinidine is a strong CYP2D6 inhibitor; flecainide is a CYP2D6 substrate. Flecainide doubles with proarrhythmic risk. BNF Appendix 1.
Symptoms
QRS widening, ventricular arrhythmias.
Management
Avoid combination. If quinidine is needed, reduce flecainide by 50%, ECG monitoring.
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 →