Comparison of ketamine and morphine for analgesia after tonsillectomy in children

Abstract

In a double blind study we compared the effects of i.m. ketamine with morphine on postoperative analgesia in children undergoing tonsillectomy. Eighty children (aged 6-15 yr) were randomized to receive either i.m. morphine 0.1-0.15 mg kg-1 or ketamine 0.5-0.6 mg kg-1, after induction of a standard general anaesthetic. Pain scores 30 min after extubation were higher (P < 0.05) in the ketamine group, but were similar thereafter to the morphine group. Mean (SD) times to recovery from anaesthesia were 20.1 (SD 6.5) min in the ketamine group compared to 14.2 (5.6) min in the morphine group (P < 0.01). There were no differences in supplemental analgesia requirements, or the incidence of vomiting or dreaming between the groups. We conclude that ketamine 0.5 mg kg-1 i.m. may be an alternative analgesic for children undergoing tonsillectomy.