Comparison of buprenorphine and methadone in the treatment of opioid dependence. Swiss multicentre study.

A three-centre, randomised, double-blind study was designed to compare the efficacy and safety of buprenorphine and methadone. This was the first European study to compare these agents and was based on a previous trial performed in the US. Opioid-dependent subjects were randomised to receive either sublingual buprenorphine or oral methadone daily. Both objective and subjective measures of efficacy were monitored weekly, and safety parameters were regularly monitored over the entire six-week study. Urinalysis showed that the two treatments were similar with a slight increase in opioid-negative urines noted in both groups. The retention rate in the buprenorphine group was lower than in the methadone group, although it has been suggested that the buprenorphine dose may have been too low for some patients. None of the side effects noted were considered serious and all were attributable to chronic opioid dependence. Experience of two years substitution treatment in Fribourg suggests that initial induction onto buprenorphine allows for patients to be subgrouped before being given the most appropriate maintenance agent. Further investigation is required into the different dose-related effects of buprenorphine seen in particular subsets of addicts.