Adherence to methadone is associated with a lower level of HIV-related risk behaviors in drug users.

There have been limited studies on the potential role of methadone treatment in HIV prevention in Asia. Over an 8-week period, we assessed the profiles of drug-taking and HIV risk behaviors, and tried to identify their relationships with methadone adherence in 690 clients who attended Hong Kong's methadone treatment program. In the preceding month, 71% of respondents reported using drugs and two-thirds of those respondents who had injected drugs at some time in their lives injected then. Infrequent clients who attended methadone clinics <2 times in the previous week were twice more likely to have injected drugs in the last month and six times more likely to have >5 injections in the last week than frequent clinic attendees. Also, clients taking <60 mg methadone daily were twice more likely to have >5 injections in the last week than those taking > or = 60 mg methadone. The findings called for further studies on harm reduction programs for HIV prevention among drug users in Asian countries.