Abstract

Injection drug users (IDUs) who are in a methadone maintenance therapy program are required to attend their drug treatment clinic on a regular basis for directly observed therapy (DOT). Such programs provide a unique opportunity to administer HAART to HIV-infected persons in this marginalized population in conjunction with their methadone therapy. A prospective observational study was conducted to determine the efficacy of directly observed antiretroviral therapy provided in conjunction with daily observed methadone maintenance therapy. A cohort of 39 patients was enrolled to receive HAART as DOT. At 48 weeks, 51% of antiretroviral-experienced patients and 65% of antiretroviral-naive patients had achieved maximum viral suppression. DOT should therefore be considered a potential option for providing HAART to IDUs, particularly when used in conjunction with methadone maintenance therapy.

Introduction

While international attention has recently focused on improving access to HAART in resource-poor countries, there remain marginalized groups of patients in developed countries who have restricted access to care. Among injection drug users (IDUs) and all other risk groups, the current standard of care for those who are HIV-infected is to individualize therapy. Antiretroviral regimens are individualized according to earlier antiretroviral exposure, pharmacokinetic data, potential drug interactions, resistance profiles, drug toxicities, and likely adherence to treatment.

One aspect of individualizing therapy for IDUs involves minimizing the impact of HAART on their daily routines. IDUs receiving stable methadone maintenance therapy are required to attend their drug treatment clinic (DTC) on a regular basis for directly observed methadone treatment. Such programs provide a unique opportunity to administer HAART to IDUs in conjunction with their methadone therapy. However, studies in large urban centers have shown that compared with other groups at risk for HIV infection, IDUs are twice as likely to not be receiving HAART -- and 3 times as likely if they are not enrolled in a DTC.^[1] Only 40% of IDUs eligible for HAART are receiving it, and only 37% of this group achieve a treatment adherence level of 80% or higher. A study conducted at the AIDS clinic in the San Francisco General Hospital showed a significant association between self-report of missed doses and detectable viremia.^[2]

What has become increasingly clear is that adherence is essential to therapeutic effectiveness and that a multidisciplinary effort is needed to meet the adherence challenge. The primary factor associated with the acceptance of HAART by IDUs is stable attendance at a methadone maintenance clinic. Several studies have shown the efficacy of directly observed antituberculous therapy,^[3,4] and the application of this method to HAART is an attractive option for IDUs.