N-acetylprocainamide

N-acetylprocainamide (NAPA), also known as acecainide, is a small molecule Class III antiarrhythmic agent and the primary active metabolite of the Class Ia antiarrhythmic procainamide. It is formed in the liver via the action of N-acetyltransferase. Unlike its parent compound, which primarily blocks sodium channels, NAPA selectively blocks delayed rectifier potassium channels, leading to a prolongation of the cardiac action potential duration and the effective refractory period. This Class III activity makes it effective for treating ventricular arrhythmias, particularly in patients who develop procainamide-induced lupus erythematosus, as NAPA has a significantly lower propensity to induce antinuclear antibodies. NAPA is primarily eliminated by the kidneys, and its pharmacokinetics are highly dependent on renal function. While it reached Phase 3 clinical trials and has been used as a research tool or in specific clinical contexts, it is not widely marketed as a standalone pharmaceutical product in many regions.

Brand names

Acecainide

Other names

N-acetyl procainamidep-acetamido-N-(2-diethylaminoethyl)benzamideAcecainidum