Metronidazole in the prophylaxis of anaerobic infections in gynecologic surgery

A double-blind study was initiated in January 1978 to determine the effectiveness of the prophylactic use of metronidazole, either orally or intravenously, in patients undergoing elective gynecologic surgery. A total of 121 women were evaluated; 42 women received oral metronidazole, 40 women intravenous metronidazole, and 39 women placebo therapy. Evidence of postoperative infection was present in 20% of patients treated with placebo, whereas in the active drug groups the incidence of infection was 12%. Blood levels of metronidazole during the operations had a mean value of 22.2 and 17.9 micrograms/ml for patients receiving intravenous and oral metronidazole, respectively. Preoperative cultures for anaerobic organisms revealed an incidence range of 23% to 45% for the three study groups. The incidence of positive anaerobic cultures declined dramatically by the second postoperative day for patients receiving intravenous and oral metronidazole, In the placebo group, the incidence was not significantly different from that in the preoperative period. This preliminary study revealed that the incidence of postoperative infections subsequent to gynecologic surgery can be reduced significantly through the use of prophylactic metronidazole.