BUPRENORPHINE REDUCES CEREBRAL GLUCOSE-METABOLISM IN POLYDRUG ABUSERS

Buprenorphine is a mixed opioid agonist-antagonist, which acts as a pa rtial mu agonist and a kappa antagonist. The present study evaluated t he acute effects of buprenorphine on cerebral glucose metabolism (CMRg lc) in six human substance abusers using a double-blind, placebo-contr olled, counterbalanced, crossover design. Each subject participated in two positron emission tomographic (PET) studies, 1 week apart, follow ing the injection of buprenorphine (1 mg, intramuscularly) and placebo . Buprenorphine significantly reduced CMRglc and the regional cerebral metabolic rate for glucose (rCMRglc) by up to 32% in all but three of 22 bilateral and in 4 midline regions (p < .05). No region showed an increase in rCMRglc. Buprenorphine also produced miosis, respiratory d epression, and subjective ratings of euphoria and sedation in comparis on to placebo (p < .05). These observations extend previous findings o f reduced CMRglc following acute treatment with morphine and other non opioid euphorigenic drugs.