Caudal clonidine for postoperative analgesia in adults

We have assessed the analgesic efficacy and side effects of caudally admini stered clonidine in a prospective, randomized, double-blind, placebo-contro lled study. We studied 64 adult patients undergoing elective haemorrhoidect omy. Caudal block was performed in all patients using a mixture of 0.5% bup ivacaine 35 mg with 2% lidocaine 140 mg and epinephrine 5 mu g ml(-1) Patie nts were allocated randomly to one of two groups. Clonidine 75 mu g was add ed in group C and saline 1 ml in group S. Median time to first analgesic re quirements 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 patient s in group C but did not affect mean arterial pressure.