BUPRENORPHINE EFFECTS ON MORPHINE-INDUCED AND COCAINE-INDUCED SUBJECTIVE RESPONSES BY DRUG-DEPENDENT MEN

The effects of daily buprenorphine treatment (4 or 8 mg/day, sublingua l) on reports of subjective effects after single intravenous doses of morphine (10 mg), cocaine (30 mg), and saline placebo were studied on an inpatient clinical research ward in 26 men concurrently dependent o n opioids and cocaine (DSM-III-R). Latency to detection and certainty of a drug effect, as well as drug quality (intensity, euphoria, and dy sphoria), were studied before and after 10 to 12 days of buprenorphine maintenance. Saline was accurately identified by all 26 patients duri ng the drugfree baseline and by 25 patients during buprenorphine maint enance conditions. All patients accurately identified morphine during the drugfree period before treatment with buprenorphine, but 18 (69%) of 26 patients were unable to detect morphine during buprenorphine mai ntenance and 2 misidentified morphine as cocaine. Six men (23%) accura tely identified morphine and reported that the intensity and quality o f morphine's effects were equivalent to drugfree conditions. Cocaine l evels in plasma 5 minutes after intravenous cocaine injection were equ ivalent before and during buprenorphine treatment and averaged 282.8 /- 43.6 and 295.2 +/- 28.8 ng/ml during 4 and 8 mg/day of buprenorphin e maintenance, respectively. All patients accurately identified cocain e before and during buprenorphine maintenance, and there were no signi ficant changes in latency to detection and certainty of a drug effect or reports of cocaine-induced intensity or euphoria during buprenorphi ne treatment. The concordance between responses to morphine and cocain e during inpatient buprenorphine maintenance and drug use during the f irst 4 weeks of outpatient buprenorphine treatment was also examined i n 16 men. The effects of buprenorphine on individual responses to an a cute intravenous dose of morphine or cocaine during the inpatient stud y did not reliably predict the frequency of heroin or cocaine self-adm inistration during the first 4 weeks of daily outpatient buprenorphine maintenance.