A Randomized, Double-Blind Trial of the Effect of Metronidazole on Pain After Closed Hemorrhoidectomy

Patients consider hemorrhoidectomy to be a painful operation. Attempts to reduce the length of inpatient stay have concentrated mainly on a reduction in postoperative pain. Metronidazole has been shown to reduce pain after open hemorrhoidectomy. The aim of this study was to evaluate the effect of metronidazole after closed hemorrhoidectomy.Thirty-eight patients undergoing closed hemorrhoidectomy were randomly allocated to receive metronidazole 400 mg (n = 18) or placebo (n = 20) three times daily for seven postoperative days. All patients received a stool softener and analgesics perioperatively. Linear analog scales were used to assess expected pain, actual pain and patient satisfaction. Time to first bowel movement, return to normal activity, complications, and use of additional analgesics were recorded.Both groups of patients experienced less pain than expected. Patients in the metronidazole group required fewer additional analgesics postoperatively (6.3 vs. 26.3 percent), and satisfaction scores in the placebo group were higher at one week (0.5 vs. 2.5), although these differences were not statistically significant. There were no differences in pain actually experienced, time to first bowel movement, return to normal activity, or complications between the two groups. Satisfaction scores at six weeks for all patients were relatively high, with no significant difference between the groups.Closed hemorrhoidectomy results in high patient satisfaction and low pain scores. The use of postoperative metronidazole did not reduce postoperative pain.