Butorphanol: a double-blind evaluation in postoperative patients with moderate or severe pain

Abstract

Informed consent was obtained from over 350 patients scheduled for major elective operations to accept either 5 or 10 mg morphine or 0.5 or 1.0 mg butorphanol (intramuscularly) under double-blind conditions according to a random assignment schedule, if they should complain of moderate to severe pain while in the recovery room. Of those consenting, 120 patients were entered in the study. The remainder either denied any pain, stated that they had only slight or mild pain, or in a few instances, refused analgesic medication although they stated they had more than mild pain. Pain intensity and pain relief were scored for each treated patient at 30, 60 and 120 minutes. Scores were analyzed statistically after tabulating the data. The data show that in virtually all these patients appreciable pain relief was admitted at the first observation period (30 minutes after administration of the drug) and it persisted for at least two hours in 90 per cent of them. No consistent alteration in the vital signs (blood pressure, pulse rate, rate of respiration or tidal volume ) was evident in these patients during the two hours they were kept under close surveillance. Approximately 10 per cent of the patients receiving butorphanol, and 15 per cent of those receiving morphine, did not request more analgesic medication; 52 per cent (butorphanol) and 42 per cent (morphine) respectively requested additional medication two to five hours after, and 25 per cent (butorphanol) and 34 per cent (morphine), respectively, requested it only after 5 hours. Analysis by the parallel line assay method produced an estimate that butorphanol ( base weight ) was on the order of ten times more potent than morphine sulfate. Due to uncertain factors, the effect of the two doses of butorphanol tested could not be distinguished two hours after medication. Drowsiness occurred early in one-third of the patients receiving butorphanol and usually persisted for several hours, whereas this effect was less prominent with morphine and was of shorter duration. Dizziness, nausea or emesis occurred in less than 5 per cent after either medication. If extensive experience with butorphanol shows that it is non-addicting and does not cause appreciable respiratory depression, it will indeed be a useful analgesic drug. © 1974 Canadian Anesthesiologists.