Adherence to heroin dependence therapies and human immunodeficiency virus/acquired immunodeficiency syndrome infection rates among drug abusers.

Adherence is a primary determinant of treatment effectiveness; thus, poor adherence attenuates optimum clinical benefit. A bibliographic review was conducted to evaluate the impact of adherence to heroin dependence treatment on human immunodeficiency virus (HIV) transmission and to identify interventions proven to be effective in improving adherence. The best adherence rates were achieved by methadone and diacetylmorphine, both of which are comparable in promoting significant reduction in heroin use. Methadone adjusted-dose studies with daily doses ranging from 100 to 200 mg and multiple support interventions achieved the highest adherence rates. Studies of methadone maintenance that examined changes in HIV prevalence of infection have found that higher treatment adherence is correlated with a reduction in HIV transmission. These data suggest that patients who adhere continuously to methadone treatment are less likely to continue injecting illicit drugs and sharing contaminated injection equipment than are those who interrupt treatment, thus preventing the spread of HIV via drug injection.