BUPRENORPHINE TREATMENT OF OPIATE AND COCAINE ABUSE - CLINICAL AND PRECLINICAL STUDIES

Buprenorphine, an opioid mixed agonist-antagonist, is a potent analges ic that appears to be effective for the treatment of opiate abuse. Rec ent preclinical studies have shown that buprenorphine also significant ly reduces cocaine self-administration by rhesus monkeys for periods u p to 120 days. This unexpected finding has led to clinical trials to e valuate buprenorphine's effectiveness for the treatment of dependence on both cocaine and opiates, as defined by DSM-III-R criteria. Bupreno rphine's safety in combination with cocaine and opiates and its effect s on electroencephalographic sleep patterns and regional cerebral bloo d flow were evaluated during inpatient studies. Buprenorphine (4 or 8 mg/day given sublingually) did not accentuate the cardiovascular and r espiratory changes induced by an acute challenge dose of cocaine (30 m g given intravenously) or morphine (10 mg given intravenously) alone. In an outpatient open trial, buprenorphine significantly reduced both opiate and cocaine abuse by patients who had abused these drugs for mo re than 10 years. Most of these patients had failed in other drug abus e treatment programs. Reports of needle sharing also decreased signifi cantly, and no patient tested positive for human immunodeficiency viru s (HIV). The apparent safety and effectiveness of buprenorphine, combi ned with a high level of patient acceptance, led the Food and Drug Adm inistration to grant a compassionate extension of the approved period for outpatient buprenorphine treatment from 26 to 52 weeks. Clinical t rials of buprenorphine are ongoing. Possible mechanisms underlying bup renorphine-cocaine interactions are now under investigation.