Caudal morphine for pain relief following anal surgery.

A prospective randomised trial was conducted to evaluate caudal morphine for pain relief following anal surgery. Thirty-three male patients were divided into two groups. Group I (17 patients) were given morphine 10 mg in saline 25 ml injected into the caudal epidural space at the end of surgery. Group II (16 patients) were given intramuscular morphine 10 mg on request in the postoperative period. Pain was assessed at 2, 6, 12 and 24 hours after surgery using the linear analogue of pain score. There was significant pain relief in Group I compared with Group II. There was no instance of respiratory depression in patients of either group. In Group I, five patients suffered urinary retention and three patients transient pruritus.