RESUMEN
The disposition of intravenous and intraperitoneal administered cefoxitin was evaluated in four males undergoing intermittent peritoneal dialysis. Each patient received 1 g of cefoxitin intravenously prior to an eight-hour dialysis; subsequently, one patient received another 1 g intravenous dose prior to an 18-hour dialysis while each of the other three patients had 100 mg of cefoxitin added to their eight hourly exchanges of dialysis fluid with 2 L per exchange. Serial blood, dialysate, and urine samples were collected and analyzed for cefoxitin by a microbiologic assay. Twenty-four hours after intravenous administration, serum cefoxitin concentrations were greater than 16 micrograms/mL (therapeutic breakpoint) in each patient. Mean cefoxitin dialysate concentrations averaged 7.8 +/- 3.8 micrograms/mL and were greater than 16 micrograms/mL in only 2 of 43 exchanges. After intraperitoneal administration, serum cefoxitin concentrations were highest after the eighth exchange (range 5.6 to 10.6 micrograms/mL). Thus, diffusion of cefoxitin across the placental membrane was not extensive. Dialysis removed only 10% to 20% of the intravenous dose.