A comparison of morphine and buprenorphine for analgesia after abdominal surgery

Abstract

Eighty fit adults having elective abdominal hysterectomy or cholecystectomy received buprenorphine or morphine intravenously at the start of peritoneal closure, in a randomised double-blind trial. The anaesthetic sequence precluded the use of other narcotic analgesics. Pain scores were lower in patients who received buprenorphine, as were the cumulative numbers of patients withdrawn from the trial at each interval because of pain, statistical significance being achieved at all intervals from one to seven hours after administration. Unexpectedly, patients having the upper abdominal procedure were more likely to receive satisfactory analgesia than those having abdominal hysterectomy. Vomiting occurred more commonly after buprenorphine, and mean respiratory rates were slightly lower. However, the differences were not statistically significant. One patient with protracted drowsiness and slow respiratory rate after buprenorphine received naloxone. No serious side-effects were noted. Buprenorphine 4-6 μg/kg provided adquate postoperative analgesia of greater duration than could be achieved with morphine, and the potency of buprenorphine when administered in this way was at least 33 times that of morphine.