Aims To test the effect of a 50-mg day−1 dose of naltrexone in the maintenance treatment of intravenous-buprenorphine dependence in comparison with a 50-mg day−1 dose of methadone and also a 5-mg day−1 dose of buprenorphine over a 24-week treatment period.
Participants Two hundred and four intravenous-buprenorphine-dependent patients who met the DSM-IV criteria for opioid dependence were randomized to three equal groups and were treated in a clinic in Iran where they were also offered a weekly 0·5-h counselling session, in 2002.
Findings The mean age was 31·2 years (range 17–53). The majority [63·2%] was between 20 and 34 years of age. The educational level of most of them [55·4%] was between 6 and 12 years of study. Completion rates by groups were 83·8% for the 50-mg dose methadone group, 58·8% for the 5-mg dose buprenorphine group and 20·6% for the 50-mg dose naltrexone group (P = 0·000). Retention in the 50-mg methadone group was significantly better than in the 5-mg dose buprenorphine group (P = 0·001) and the 50-mg dose naltrexone group (P = 0·000). Retention in the 5-mg buprenorphine group was significantly better than in the 50-mg naltrexone dose group (P = 0·000).
Conclusions Evaluation of the Iranian experience on this subject may be useful for other countries.