Intentional Medication Nonadherence Because of Interactive Toxicity Beliefs Among HIV-Positive Active Drug Users.

Background: Drug use poses significant challenges to medical management of HIV infection. Although most research has focused on the influence of intoxication on unintentional adherence to HIV treatment, drug use may also lead to intentional nonadherence, particularly when individuals believe that mixing medications with drugs is harmful. This study examined whether interactive toxicity beliefs predict nonadherence to antiretroviral therapy (ART) over a prospective period of adherence monitoring.

Methods: Men and women living with HIV who screened positive for drug use and were being treated with ART (n = 530) completed computerized self-interviews and 3 prospective unannounced pill counts to measure ART adherence and provided urine specimens for drug screening and HIV viral load results from medical records.

Results: Results showed that 189 (35%) participants indicated that they intentionally miss their ART when they are using drugs. These participants also reported common beliefs regarding the perceived hazards of mixing HIV medications with alcohol and other drugs. Multivariable models controlled for demographic and health characteristics and frequency of alcohol use showed that intentional nonadherence predicted poorer ART adherence over the prospective month and also predicted poorer treatment outcomes as indexed by unsuppressed HIV viral load.

Conclusions: These findings extend previous research to show that interactive toxicity beliefs and intentional nonadherence play a significant role in medication nonadherence for a substantial number of people living with HIV and should be actively addressed in HIV clinical care.