Pharmacokinetics of aztreonam administered i.p. in continuous ambulatory peritoneal dialysis (CAPD) patients

The pharmacokinetics of Aztreonam (AZT) administered i.p. in six stable patients undergoing continuous ambulatory peritoneal dialysis (CAPD) for end-stage renal disease (ESRD) were studied. One gram of AZT was added into a 2 L bag of dialysate (Medital-Bieffe) just prior to infusion into the peritoneal cavity. The dwell time was 8 h. The serum maximum concentration of AZT was 42.5 +/- 12.4 mg/L (mean +/- SD), achieved in 4.6 +/- 1.0 h. The elimination half-life was 2.4 +/- 0.8 h, almost equal to that found in normal subjects (1.7-2 h). The pharmacokinetic parameters of elimination, as elimination rate constant and clearance of AZT from peritoneal cavity were found 0.305 +/- 0.101 h-1 and 10.05 +/- 3.7 mL/min, respectively, while the bioavailability via the peritoneal membrane was 90.8 +/- 3.05% of administered dose. It is concluded that AZT is eliminated from dialysate at a high rate after i.p. administration and its dialysate and serum levels exceed the MIC for the majority of sensitive organisms including Pseudomonas species. Aztreonam appears to be a potentially useful antibiotic for CAPD peritonitis.