SPECT REGIONAL CEREBRAL BLOOD-FLOW ALTERATIONS IN NALTREXONE-PRECIPITATED WITHDRAWAL FROM BUPRENORPHINE

The effects of naltrexone-precipitated withdrawal from buprenorphine o n behavior and regional cerebral blood now (rCBF) were studied in 11 o piate-dependent patients. Patients initially received buprenorphine, 2 mg sublingually, every day for 7 days. They were then challenged sequ entially with placebo and naltrexone, 25 mg orally, before single phot on emission computed tomography with technetium-(99)m-d,l-hexamethyl-p ropylene amine oxime as tracer. Behavioral ratings of withdrawal sever ity were made before and after naltrexone/placebo administration. Nalt rexone produced significantly greater signs and symptoms of opiate wit hdrawal than placebo. Analysis of variance revealed no significant reg ionally specific effect of naltrexone on rCBF ratios. Severity of with drawal, however, showed a significant negative correlation with rCBF i n the anterior cingulate cortex following naltrexone. These results ar e interesting as the anterior cingulate region has been implicated in the emotional component of pain and in opiate-induced analgesia.