BUPRENORPHINE - DOSE-RELATED EFFECTS ON COCAINE AND OPIOID USE IN COCAINE-ABUSING OPIOID-DEPENDENT HUMANS

Fifteen subjects dependent on both opioids and cocaine completed an as cending and tapering schedule of buprenorphine dosing, with maintenanc e for 21 days at each dose of buprenorphine (4, 8, 12, 16 mg sublingua l daily) during both ascending and tapering phases. Higher doses of bu prenorphine led to greater reductions in opioid use: 64.7% of subjects were opioid abstinent for 3 weeks at the 16-mg dose compared to 27.3% at the 4-mg ascending dose. The proportion of cocaine-positive urine toxicologies was significantly lower during buprenorphine tapering (12 mg, 8 mg, 4 mg) compared to ascending doses up to 8 mg, with intermed iate results at 12 mg and 16 mg during the ascending phase (F value = 6.6, df = 8, 813, p < 0.001). Self-reported days, times, and quantity of cocaine used per week showed a similar pattern of intermediate redu ctions at the 12-mg and 16-mg dose during the ascending phase and sign ificantly reduced values during the descending schedule. There were no significant buprenorphine dose effects on cocaine euphoria. This stud y indicates that buprenorphine dose has a significant and substantial impact on opioid use and a significant but less robust impact on cocai ne use, with higher doses and longer time on buprenorphine leading to attenuated cocaine use.