Comparing the subjective, psychomotor and physiological effects of intravenous buprenorphine and morphine in healthy volunteers.

The purposes of this study were to characterize the subjective, psychomotor and physiological effects of buprenorphine in nondrug-abusing volunteers and to compare and contrast the effects of equianalgesic doses of buprenorphine and morphine. Sixteen subjects without histories of opiate dependence were injected in an upper extremity vein with 0, 0.075, 0.15 or 0.3 mg/70 kg buprenorphine, or 10 mg/70 kg morphine, using a randomized, double-blind, cross-over design. The 0.3-mg buprenorphine dose and 10-mg morphine dose are considered to be equianalgesic and are doses commonly given for relief of postoperative pain. Buprenorphine increased scores on the Pentobarbital-Chlorpromazine-Alcohol Group scale and decreased scores on the Benzedrine Group scale of the Addiction Research Center Inventory, increased adjective checklist ratings of "nodding," "skin itchy," and "turning of stomach," and increased visual analogue scale ratings of "dizzy," "nauseous" and "sleepy." Buprenorphine (0.3 mg) in general had subjective effects of greater magnitude than that of 10 mg morphine. Buprenorphine produced impairment on five measures of psychomotor performance in a dose-related fashion. Ten mg morphine produced minimal psychomotor impairment. Both buprenorphine and morphine induced miosis, but buprenorphine (0.3 mg) had a larger and longer effect than that of 10 mg morphine. Buprenorphine, but not morphine, decreased respiration rate. The results of our study demonstrate that 0.075 to 0.3 mg buprenorphine had orderly, dose-related effects on subjective, psychomotor and physiological variables. Further, a clinically relevant dose of buprenorphine, 0.3 mg, produced a greater magnitude of subjective and psychomotor-impairing effects than did an equianalgesic dose of morphine.