Cefoxitin serum and uterine concentrations following a two-gram intramuscular dose

Two grams of cefoxitin was administered intramuscularly to 31 premenopausal women when they were called to the operating room for a scheduled vaginal hysterectomy. Serum and tissue samples were obtained to determine cefoxitin concentration. The mean concentration of cefoxitin at the reported peak in serum after an intramuscular injection (30 minutes) was 25.3 micrograms/ml. The mean serum concentration at the time of uterine excision (a mean of 143 minutes after the on-call dose) was 18.0 micrograms/ml. The mean concentrations of cefoxitin in the uterine fundus and the lower uterine segment at the time of uterine excision were 1.1 and 1.8 micrograms/g tissue, respectively.