Int. J. Environ. Res. Public Health 2012, 9 202 Reference Interventions Study characteristics Duration Outcome Comments Mattick et al. 2003 [36] Mattick et al. 2008 [37] Gowing et al. 2006 [38] Methadone maintenance versus tapering Buprenorphine or placebo buprenorphine, clonidine, other active, but not placebo RCTs RCTs RCTs or quasi randomised trials Table 1. Cont. Various times, largely of the order of 6 months Shortest 4 week, others 2 months or longer Mostly short term Retained in treatment Drug free urine Retained in treatment opioid free Number completing programme, presumably drug free, but that is not explicitly stated Abstinence with Intervention Placebo Methadone Tapered maintenance: Retained: 63/251 Retained 173/254 (25%) (68%) DFU: 49/214 DFU: 103/195 (53%) (23%) Buprenorphine Placebo Opioid free: 495/742 Opioid free: (67%) 202/476 (42%) Buprenorphine 317/506 (63%) Clonidine 155/378 (41%)