A preliminary investigation comparing pre-operative morphine and buprenorphine for postoperative analgesia and sedation in cats

Objective To compare the postoperative analgesic and sedative properties of buprenorphine and morphine in cats. Study Design Prospective, randomized, blinded study. Animals Thirty-two domestic cats undergoing surgery. Methods Cats received pre-anaesthetic medication with acepromazine (0.05 mg kg(-1)) given intramuscularly and were randomly allocated to group M and given morphine (0.1 mg kg(-1)) intramuscularly (IM) or to group B and given buprenorphine (0.01 mg kg(-1)) IM. Anaesthesia was induced with propofol and maintained with halothane in oxygen and nitrous oxide. Pain and sedation scores using visual analogue scales, and heart and respiratory rates, were measured immediately before, and 30, 60,120, 180,300 and 420 minutes after anaesthesia. Results Pain scores were significantly lower at 60, 120 and 180 minutes after anaesthesia in group B. Group B also had higher heart rates at 30 minutes. There were no other statistically significant differences between the groups. Clinical relevance Buprenorphine (0.01 mg kg(-1)) appeared to provide better postoperative analgesia than morphine (0.1 mg kg(-1)) and may also have a longer duration of action.