Topical nifedipine with lidocaine ointment versus active control for pain after hemorrhoidectomy: results of a multicentre, prospective, randomized, double-blind study.

BACKGROUND: Spasm through the internal anal sphincter is one of the supposed causes for pain after hemorrhoidectomy, a common and distressing experience. We hypothesized that the addition of topical nifedipine to lidocaine would improve pain control by causing a relaxation of the smooth muscle of the internal anal sphincter.

METHODS: We conducted a multicentre randomized, double-blind trial to compare the efficacy of 0.3% nifedipine and 1.5% lidocaine ointment versus 1.5% lidocaine ointment alone in reducing pain after hemorrhoidectomy. A physician unaware of the treatment arm measured pain by use of the Analogue Chromatic Continuous Scale (ACCS) at baseline; soon after surgery; at 2, 4, 6, 8 and 24 hours after surgery; on day 7 after surgery; and at a final visit 14 days after surgery. The physician also noted the time to first analgesic administration within 24 hours after surgery.

RESULTS: In all, 135 patients per group participated (270 total). Evaluation of the delta ACCS score versus basal value, a covariate for rescue analgesic administration time, revealed better pain control in the group that received nifedipine with lidocaine at 6 hours after surgery and on day 7 (p < 0.011 and p < 0.054, respectively). We noticed no difference between groups for time of administration of rescue analgesic, blood pressure, heart rate or frequency of headache.

CONCLUSION: Although there was no difference between groups for time of administration of rescue analgesic after open hemorrhoidectomy, the patients' assessment of pain using ACCS showed that the use of topical nifedipine with lidocaine may provide a slight significant difference in favour of the study group at 6 hours and at day 7 after surgery. Narcotic analgesics and nonsteroidal anti-inflammatory drug administration should continue to be recommended. Further research focusing on these outcomes is warranted.