Comparison between buprenorphine and pentazocine given i.v. on demand in the control of postoperative pain.

A double-blind comparison between buprenorphine and pentazocine was performed in 20 patients using an on demand analgesic system to provide analgesia after operation. The quality of analgesia, assessed subjectively, was good with both drugs and drug consumptions were compatible with previous potency estimates. The mean doses demanded in 24 h of buprenorphine (1.68 mg) and of pentazocine (382 mg) are consistent with those found in other trials although the between-patient variation was five- or six-fold. There was no significant difference in side-effects between the two groups. Buprenorphine and pentazocine may be used successfully in an on demand system to provide relief of severe pain after operation.