Peroperative buprenorphine: do high dosages shorten analgesia postoperatively?

Fifty-two patients undergoing biliary surgery were investigated in a prospective randomized study, in which they received buprenorphine 10, 20, 30, and 40 micrograms X kg-1, respectively, as sole intravenous analgesic as a bolus 15 min before induction of anaesthesia. The anaesthetic was uneventful in all four groups, although when receiving 10 and 20 micrograms X kg-1 almost two-thirds of the patients needed supplemental analgesics during the operation. When receiving buprenorphine in the dosage of 30 and 40 micrograms X kg-1, 50% of the patients requested an analgesic within 5 min of extubation. In contrast, when receiving 10 and 20 micrograms X kg-1 none of the patients requested an analgesic within 1 h of the operation. These findings accord to a certain extent with the presence of a bell-shaped dose-response curve for buprenorphine in humans.