Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Many drugs besides flecainide may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, and macrolide antibiotics (such as erythromycin), among others.

Other medications can affect the removal of flecainide from your body, which may affect how flecainide works. Examples include asunaprevir, cimetidine, fluconazole, certain HIV protease inhibitors (such as tipranavir), ritonavir, anti-seizure drugs (such as phenytoin, phenobarbital), among others.