Buprenorphine maintenance versus placebo or methadone maintenance for opioid dependence

Background Buprenorphine has been reported as an alternative to methadone for maintenance treatment of opioid dependence, but differing results are reported concerning its relative effectiveness indicating the need for an integrative review. Objectives To evaluate the effects of buprenorphine maintenance against placebo and methadone maintenance in retaining patients in treatment and in suppressing illicit drug use. Search strategy We searched the following databases up to October 2006: Cochrane Drugs and Alcohol Review Group Register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE, Current Contents, Psychlit, CORK, Alcohol and Drug Council of Australia, Australian Drug Foundation, Centre for Education and Information on Drugs and Alcohol, Library of Congress databases, reference lists of identified studies and reviews, authors were asked about any other published or unpublished relevant RCT. Selection criteria Randomised clinical trials of buprenorphine maintenance versus placebo or methadone maintenance. Data collection and analysis Authors separately and independently evaluated the papers and extracted data for meta- analysis. Main results Twenty four studies met the inclusion criteria ( 4497 participants), all were randomised clinical trials, all but six were double- blind. The method of allocation concealment was not clearly described in the majority ( 20) of the studies, but where it was reported the methodological quality was good. Buprenorphine was statistically significantly superior to placebo medication in retention of patients in treatment at low doses ( RR= 1.50; 95% CI: 1.19 - 1.88), medium ( RR= 1.74; 95% CI: 1.06 - 2.87), and high doses ( RR= 1.74; 95% CI: 1.02 - 2.96). The high statisitical heterogenity prevented the calculation of a cumulative estimate. However, only medium and high dose buprenorphine suppressed heroin use significantly above placebo. Buprenorphine given in flexible doses was statistically significantly less effective than methadone in retaining patients in treatment ( RR= 0.80; 95% CI: 0.68 - 0.95), but no different in suppression of opioid use for those who remained in treatment. Low dose methadone is more likely to retain patients than low dose buprenorphine ( RR= 0.67; 95% CI: 0.52 - 0.87). Medium dose buprenorphine does not retain more patients than low dose methadone, but may suppress heroin use better. There was no advantage for medium dose buprenorphine over medium dose methadone in retention ( RR= 0.79; 95% CI: 0.64 - 0.99) and medium dose buprenorphine was inferior in suppression of heroin use. Authors' conclusions Buprenorphine is an effective intervention for use in the maintenance treatment of heroin dependence, but it is less effective than methadone delivererd at adequate dosages.