Pharmacokinetics of intravenous and intraperitoneal ceftazidime in chronic ambulatory peritoneal dialysis

The pharmacokinetics of ceftazidime have been investigated in eight patients with chronic renal failure undergoing continuous ambulatory peritoneal dialysis. Each subject was given ceftazidime 1 g intravenously and 1 g intraperitoneally at an interval of 1 week. Ceftazidime was assayed by high-pressure liquid chromatography. After intravenous administration, the pharmacokinetic parameters of ceftazidime were: elimination plasma half-life (t1/2 beta) = 24.6 +/- 4.6 hours; apparent volume of distribution (V(area)): 0.37 +/- 0.09 1/kg, total plasma clearance (CL): 11.9 +/- 3.3 mL/minute, peritoneal clearance (CLp): 1.7 +/- 0.3 mL/minute. Over 72 hours, only 15.6 +/- 4.7% of the dose was eliminated by the peritoneal route. After intraperitoneal administration, ceftazidime appeared in the plasma rapidly, and the peak plasma concentration of 24.5 +/- 5.2 mg/L was achieved at the fourth hour; the elimination half-life (t1/2ke) was 20.8 +/- 1.7 hours. The absorption of ceftazidime from the peritoneal space was 74.1 +/- 7.4%. These data suggest that ceftazidime has bidirectional exchange characteristics through the peritoneal membrane. A single 1-g intraperitoneal dose led to serum and dialysate concentrations of ceftazidime above the minimum concentrations for susceptible pathogen germs for 24 hours.