THE RESPIRATORY EFFECTS OF A POTENT ANALGESIC (GPA 2087) IN MAN

The respiratory depressant effects of a potent analgesic (GPA2087) were compared with morphine in a randomized double-blindcross-over study in human volunteers. Using a rebreathing technique,carbon dioxide response curves were plotted automatically witha special-purpose analog computer. The respiratory depressantrelative potency of GPA 2087 to morphine was found to be 1.21with lower and upper 95 per cent confidence limits of 0.88 and2.04. Our best estimate based on the displacement of the respiratoryresponse curve is that GPA 2087 8 mg is the equivalent of morphine10 mg in our population of volunteers. ^*Geigy Pharmaceuticals, Ardsley, New York, U.S.A.^*Present address: Salisbury General Infirmary, Odstock Branch,Salisbury, Wiltshire, England.