Comparison of the pharmacokinetic and pharmacodynamic properties of procainamide and N-acetylprocainamide.
Although procainamide (PA) has been widely used to treat patients with both ventricular and supraventricular arrhythmias since 1951, more than twenty years elapsed before N-acetylprocainamide (NAPA) was identified as a major PA metabolite and shown in PA-treated patients to have plasma concentrations generally equaling or being 2 to 3 times greater than those of the parent drug. Numerous investigations have been conducted since then to characterize the pharmacokinetics and pharmacodynamics of NAPA and to compare these properties with those of PA. Salient differences have been that the elimination half-life of NAPA is 2.5 times that of PA, even when renal function is normal; that NAPA has a spectrum of electrophysiologic action that differs from PA in that NAPA only prolongs action potential duration; and that NAPA is less likely than PA to cause a syndrome resembling systemic lupus erythematosus. Although these properties have provided an impetus for the development of NAPA as an antiarrhythmic drug in its own right, emphasis is placed in this review on the implications of these findings for individualizing PA therapy.
Atkinson
A J
AJ
Clinical Pharmacology Center, Northwestern University Medical School, Chicago, Illinois.
Ruo
T I
TI
Piergies
A A
AA
D000120:Acecainide / Q000493:pharmacokinetics / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D004594:Electrophysiology; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D011342:Procainamide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology*
D000120:Acecainide; D011342:Procainamide