Effects of meclofenamate and acetaminophen on abdominal pain following tubal occlusion.

To test the hypothesis that the postoperative abdominal pain of tubal occlusion is mediated by prostaglandins, the effects of meclofenamate, a potent inhibitor of cyclooxygenase, on postoperative analgesia and incidence of abdominal pain were compared with those of acetaminophen, a weak inhibitor of prostaglandin activity. One hundred patients undergoing tubal occlusion under local anesthesia were studied. The patients were randomly divided into four equal groups: control; acetaminophen, 1300 mg; meclofenamate, 100 mg; meclofenamate, 200 mg. The fallopian tubes were occluded by electrocautery in 47 patients and by application of Falope rings in 53 patients. Both acetaminophen and meclofenamate provided substantial analgesia for 4 hours after the operation (p less than 0.05). Meclofenamate reduced the incidence of abdominal pain by one half (p less than 0.02), but acetaminophen did not. These results suggest that a portion of pain relief achieved by meclofenamate may be due to suppression of myosalpingian and/or myometrial contractions, a process mediated by prostaglandins.