Pharmacokinetics of cefoxitin in patients with pleural effusion on a multiple dosage regimen.

The pharmacokinetics of cefoxitin were studied in 6 healthy volunteers and in 5 patients with pleural effusion of varied etiologies. The antibiotic was administered in a multiple dosage regimen of 30 mg/kg every 8 hours. Cefoxitin concentrations in serum and pleural fluid were determined after administration of the third dose corresponding to the levels of steady-state in both fluids. The elimination half-life of the antibiotic from the pleural fluid comes to 3.51 +/- 1.15 h, which is significantly greater than the serum half-life, (t 1/2 = 1.42 +/- 0.51 h). This kind of multiple dosage regimen ensures therapeutic levels of cefoxitin in the pleural fluid during the entire treatment.