Buprenorphine hydrochloride: determination of analgesic potency.

An open evaluation of relief from severe pain following major abdominal operations was carried out on at least ten patients, who had given written consent, with 0.1 to 0.4 mg doses of buprenorphine hydrochloride administered intramuscularly. Statistical analysis of the data showed that 0.3 mg of this compound provided quite satisfactory relief from pain for up to six hours. Seven more consenting patients were given buprenorphine hydrochloride 0.5 to 0.6 mg, but they did not receive much greater or longer pain relief than those receiving 0.3 to 0.4 mg. However, the latter patients were younger and heavier. It was concluded that buprenorphine hydrochloride 0.2 to 0.4 mg provided relief of severe pain probably as well as is observed with morphine 10 mg for the average-size patient, but the duration of pain relief with the new compound is substantially longer than with other strong analgesics previously tested. The only common side effect noted was drowsiness, which was observed during the analgesic action of the compound. No appreciable alterations were seen in the respiration, pulse rate and blood pressure. On the basis of these tests, buprenorphine hydrochloride appears to be a satisfactory analgesic for severe postoperative pain, and it deserves extensive study.