Flecainide Acetate Interactions

There has been little experience with the coadministration of flecainide acetate and either disopyramide or verapamil . Because both of these drugs have negative inotropic properties and the effects of coadministration with flecainide acetate are unknown, neither disopyramide nor verapamil should be administered concurrently with flecainide acetate unless, in the judgment of the physician, the benefits of this combination outweigh the risks.

Source: FDA drug label - flecainide acetate

There has been too little experience with the coadministration of flecainide acetate with nifedipine or diltiazem to recommend concomitant use.

Source: FDA drug label - flecainide acetate

In a study involving healthy subjects receiving flecainide acetate and propranolol concurrently, plasma flecainide levels were increased about 20% and propranolol levels were increased about 30% compared to control values. In this formal interaction study, flecainide acetate and propranolol were each found to have negative inotropic effects; when the drugs were administered together, the effects were additive. The effects of concomitant administration of flecainide acetate and propranolol on the PR interval were less than additive.

Source: FDA drug label - flecainide acetate