Pharmacokinetics of intraperitoneal ciprofloxacin in patients on CAPD

The concentration of ciprofloxacin was assayed in plasma and peritoneal dialysate following intraperitoneal administration of the drug in the absence of bacterial peritonitis. After administration of a single dose of 5 mg/kg, ciprofloxacin was rapidly absorbed, producing a peak plasma concentration of 1.9 +/- 0.6 mg/l after 3-4 h with an apparent bioavailability of 0.84. In a separate study, following the administration of 25 mg/l for eight consecutive CAPD cycles the intraperitoneal concentration of ciprofloxacin fell to a mean of 8.4 +/- 4.6 mg/l after 4 h cycles and to a mean of 3.0 +/- 3.2 mg/l after 12 h cycles. During the period of administration the mean plasma concentration was 0.5 +/- 0.2 mg/l. Analysis of dialysate for 48 h after cessation of drug administration demonstrated ciprofloxacin to be present in effluent from only two of the six patients, confirming its poor peritoneal elimination.