Pleural fluid levels of cefoxitin in patients with renal impairment.

The pharmacokinetics of cefoxitin was studied in 14 patients with a pleural effusion, 8 of which had normal renal function and the other 6 varying degrees of renal impairment. All patients received a single dose of 30 mg/kg i.v. bolus of the antibiotic. The serum and pleural fluid concentrations of cefoxitin were determined microbiologically. The serum elimination half-life of the antibiotic in the group of patients with normal renal function had a mean value of 1.35 +/- 0.56 h while that of the second group ranged between 2.00 h and 40.79 h, according to the deterioration in renal function. The disappearance half-life of cefoxitin from pleural fluid increased parallel to the degree of renal impairment, reaching a value of 30.09 h for a creatinine clearance (Ccr) of 5.8 ml/min. From the data obtained, dosage regimens were programmed according to the degree of renal function with the aim of achieving safe and efficient cefoxitin levels in both biological fluids.