Serum and dialyzate concentrations of intraperitoneal cephalothin in patients undergoing continuous ambulatory peritoneal dialysis.

The pharmacokinetics of cephalothin sodium were studied in seven patients with chronic renal failure undergoing continuous ambulatory peritoneal dialysis. 100 mg of cephalothin per liter dialyzate were administered intraperitoneally during nine dialysis cycles with 2 liters of dialysis fluid per cycle. Serum levels of the antibiotic, measured microbiologically during the first, fifth and ninth dwell time, revealed peak values of 3.5 +/- 1.7 mg/l, 5.6 +/- 2.2 mg/l and 5.3 +/- 2.5 mg/l, respectively. The mean concentration in the dialysis outflow was 23.6 +/- 15.6 mg/l (range: 2.0-78.7 mg/l). Intraperitoneally administered cephalothin is well tolerated. Serum levels exceeded the minimal inhibitory concentrations of most gram positive bacteria causing peritonitis in these patients.