Pharmacokinetics of procainamide in continuous ambulatory peritoneal dialysis

Procainamide (PA) and N-acetylprocainamide (NAPA) pharmacokinetics were examined in six patients undergoing continuous ambulatory peritoneal dialysis (CAPD) following a single oral dose of 625 mg of procainamide HCl. Peak serum PA concentrations occurred between 1 and 3 h after drug administration whereas peak NAPA levels were reached 14 to 48 h following the administration of PA. NAPA levels 1.2 mcg/ml or greater were present for 72 h and in four of the six subjects little further decline occurred at 96 h. PA total body clearance (TBC) averaged 143 ml/min; TBC for NAPA was 29.8 ml/min. PA and NAPA half-lives were considerably prolonged averaging 26.0 and 42.8 h, respectively. V beta for PA was 4.1 l/kg and for NAPA was 1.46 l/kg. PA and NAPA dialysance varied from 0.28 to 5.55 ml/min and from 1.74 to 7.20 ml/min, respectively. This, in turn, represented less than 5 and 25% of the TBC for each drug.