EFFECT OF AGE, GENDER, AND RACE ON STEADY-STATE PROCAINAMIDE PHARMACOKINETICS AFTER ADMINISTRATION OF PROCANBID SUSTAINED-RELEASE TABLETS

Procainamide hydrochloride is a Class 1A antiarrhythmic agent administ ered intravenously or orally for treatment of symptomatic ventricular premature depolarizations (VPD), nonsustained ventricular tachycardia, and life-threatening ventricular arrhythmias. A new sustained-release formulation, Procanbid, which allows for twice-daily dosing was recen tly approved for marketing in the United States. This paper describes the population pharmacokinetics of procainamide and N-acetylprocainami de (NAPA), the major metabolite, in healthy volunteers and patients wi th VPD by combining C-max, t(max), C-min, and AUC(0-12) values at stea dy state from six multiple-dose studies in which one 1000-mg or two 50 0-mg Procanbid tablets were administered. Means of parameters by race and gender were inspected for trends likely to be of clinical relevanc e. Procainamide and NAPA pharmacokinetic parameters observed after adm inistration of Procanbid tablets were similar in blacks and whites, an d in men and women. However, differences in body size should be consid ered when determining the Procanbid dose for women. Participant age ha d significant impact an NAPA pharmacokinetics in this study population and should be considered in dose selection. Age effects on procainami de were not detected in the study population, which was heavily weight ed toward younger subjects, but are anticipated in the older populatio n of patients for which procainamide is indicated. Procanbid formulati on performance was not altered by patient demographics.