A double blind comparison of buprenorphine and morphine in conscious subjects following administration by the intramuscular route.

Buprenorphine was studied to determine the respiratory depressant effect in a double blind comparison with morphine. Buprenorphine produced a more prolonged displacement of the carbon dioxide response curve than morphine. Because of the marked difference in the time effect curves the relative potency was determined at the time of peak effect--3 hours post-administration for buprenorphine (0.15 and 0.3 mg) and 1 hour post administration for morphine (5 and 10 mg). The data from the subjects who received higher doses of buprenorphine (0.6 and 1.2 mg) showed that there was a linear relationship over the dose range 0.15-1.2 mg in terms of respiratory depression.