Comparative intraoperative concentrations of two cephalosporins with activity against anaerobic bacteria.

We determined the intraoperative concentrations of cefmetazole and cefoxitin in serum and muscle from the wound of 30 patients who were undergoing cholecystectomies. The study employed an open-label design in which all patients randomly received cefoxitin sodium (30 mg/kg) or cefmetazole sodium (15 or 30 mg/kg) intravenously with the induction of anesthesia. Total serum and wound-muscle concentrations achieved with cefmetazole 30 mg/kg were significantly greater than those achieved with a similar dose of cefoxitin. Cefmetazole in a 15 mg/kg dose was comparable with cefoxitin 30 mg/kg in achieved concentrations. The elimination half-life for cefoxitin was much shorter than that for cefmetazole (41 min v. 64-68 min, respectively) and this relates to a shorter duration of action for the former. The choice of agent for surgical prophylaxis should incorporate factors relating to drug pharmacokinetic properties as well as microbiological factors.