The pharmacokinetics of vancomycin were studied in four patients on continuous ambulatory peritoneal dialysis. After a single intravenous infusion of 10 mg/kg of total body weight, multiple blood, urine, and dialysate samples were collected during a 72-h evaluation period. The steady-state volume of distribution was 0.73 ± 0.07 (mean ± standard deviation) liters/kg with a beta half-life of 90.2 ± 24.2 h. The continuous ambulatory peritoneal dialysis clearance of vancomycin was 1.35 ± 0.35 ml/min, and the serum clearance was 6.4 ± 1.1 ml/min. Peritoneal dialysate concentrations of vancomycin were rapidly attained after the intravenous infusion and averaged 2.2 ± 0.7 mg/liter throughout the 72-h observation period. A loading dose of 23 mg/kg followed by a maintenance dose of 17 mg/kg every 7 days should attain and maintain therapeutic serum and dialysate concentrations. More frequent dosing may be necessary for less susceptible organisms.Continuous ambulatory peritoneal dialysis (CAPD) is a self-dialysis procedure which is now widely used for the management of end-stage renal disease. The most frequent complication of CAPD is peritonitis. Over 65% of these infections are caused by gram-positive organisms, and ca. 50% are due to staphylococcal species (P. K. Peterson, and W. F. Keane, in J. S. Remington and M. N. Swartz, ed., Current Clinical Topics in Infectious Diseases, in press). Clinical effectiveness of vancomycin against staphylococci is well documented (1,5,7,9,14). The MICs of vancomycin have ranged from 0.63 to 3.12 mg/liter for Staphylococcus aureus and from 1.56 to 3.12 mg/liter for Staphylococcus epidermidis (6,8,10,16). Thus, vancomycin could be an extremely useful antibiotic for the management of infections in the CAPD patient.The pharmacokinetics of intravenously administered vancomycin in patients undergoing CAPD have, until recently, not been rigorously evaluated (4). The purpose of this study was to assess vancomycin concentrations in serum, periotoneal dialysate fluid, and urine after administration of a single intravenous dose. The pharmacokinetic parameters determined are as follows: elimination rate, elimination halflife, volume of distribution, total body clearance, and peritoneal clearance.MATERIALS AND METHODS Patients. Four patients (two males and two females) with end-stage renal disease undergoing CAPD gave written, informed consent to participate in this study. All patients had been on CAPD for at least 2 months (range, 2 to 14 months), and none had experienced peritonitis in the previous 2 months. Patients requiring systemic antibiotic therapy or who had a known allergy to vancomycin were excluded. Each patient had a physical examination and a laboratory screening profile done before and after they were studied.All patients had an indwelling Tenckhoff catheter in place. The CAPD exchange schedule for all patients was 2 liters of * Corresponding author. 2.5% glucose peritoneal dialysis solution (PD I; TravenolLaboratories, Deerfield, Ill.) four times a day. An intravenous catheter was ...