Treating hepatitis C virus infection in active substance users.

Although injection drug users represent the majority of new and existing cases of infection with hepatitis C virus (HCV), many lack access to treatment because of concerns about adherence, effectiveness, and reinfection. On the basis of on a small but increasing body of evidence showing that injection drug users can undergo treatment for HCV infection successfully, the 2002 National Institutes of Health Consensus Statement on Hepatitis C has recommended that substance users be treated for HCV infection on a case-by-case basis. However, the criteria on which these treatment decisions should be made are unclear. The duration of pretreatment abstinence, concurrent psychiatric illness, intervening drug use, and the potential for injected interferon to cause relapse of drug use may all influence results of treatment for HCV infection. This overview presents preliminary data on the impact of these potential barriers on outcomes of treatment for HCV infection.