Caudal clonidine for postoperative analgesia in adults.

Abstract

We have assessed the analgesic efficacy and side effects of caudally administered clonidine in a prospective, randomized, double-blind, placebo-controlled study. We studied 64 adult patients undergoing elective haemorrhoidectomy. Caudal block was performed in all patients using a mixture of 0.5% bupivacaine 35 mg with 2% lidocaine 140 mg and epinephrine 5 micrograms ml-1. Patients were allocated randomly to one of two groups. Clonidine 75 micrograms was added in group C and saline 1 ml in group S. Median time to first analgesic requirements was significantly longer in group C (mean 729 (SD 120) min) than in group S (276 (131) min) (P = 0.01). Bradycardia occurred in seven patients in group C but did not affect mean arterial pressure.