A comparison of intramuscular and sublingual buprenorphine, intramuscular morphine and placebo as premedication.

Buprenorphine premedication by two routes, 0.4 mg sublingual and 0.3 mg intramuscular was compared double-blind, double-dummy with intramuscular morphine 10 mg and placebo in 74 patients undergoing elective total hip replacement. Anxiety, depressive mood, sedation, vital signs and side-effects were measured before surgery. All patients then received a standardised general anaesthetic using a muscle relaxant and ventilation. The effects of the premedication on the anaesthetic were assessed by a scoring system. Intra- and postoperative blood gases, plasma cortisol and glucose were measured and the 1 hour postoperative pain intensity, side-effects and sedation were assessed. No differences between the premedications were seen on any of the pre-, intra- or postoperative measurements, suggesting that even with adequate measurement sensitivity it is difficult to distinguish opiate from placebo premedication.