Current concepts of procainamide therapy

Procainamide is an effective agent for suppressing ventricular and supraventricular dysrhythmias, and recent investigations reveal that a metabolite, N-acetylprocainamide (NAPA), also has antidysrhythmic action. NAPA, which is excreted unchanged by the kidney, is found in high concentrations in the plasma of patients with renal failure. Further, procainamide may induce a systemic lupus erythematosus-like reaction in some chronic users, and the ratio of plasma procainamide to NAPA in patients on procainamide may by predictive of the risk of developing this immunologic reaction. These recent investigations have enhanced our ability to use procainamide more safely and more effectively.