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Background: Clinical trials have shown that therapeutic drug monitoring (TDM) of antiretrovirals (ARV) improves patient care. However, little is known about the usefulness of TDM in routine practice., Method: We reviewed all the trough concentrations of protease inhibitors and nonnucleoside reverse transcriptase inhibitors that were performed for therapeutic failure, suspected drug toxicity, or routine purposes., Results: Between 1998 and 2001, 146 TDMs were done in 109 HIV patients. Of the 48 patients with therapeutic failure, 62% had resistance to ARV with adequate ARV concentrations, 16% had insufficient drug exposure without any ARV resistance mutations, and 16% combined both resistance and suboptimal drug concentrations. Subsequent therapeutic interventions (increasing adherence and/or changing HAART) resulted in an undetectable viral load in 37.5% of the patients (14/48). Five (24%) of 21 patients with suspected drug toxicity had high drug concentrations associated with side effects. In all the cases, adverse events regressed after reduction of drug dosage. Of the 77 TDMs done for routine purposes, 26% were outside the therapeutic range., Conclusion: The data show that TDM of ARVs in the clinical setting provides important information that can be used to improve the management of HIV patients receiving antiretroviral therapy.

Purpose: Adherence to antiretroviral medications is critically important for the success of therapy in patients treated for HIV infection. Patient self-report is a simple method to measure and explore adherence. Even though a variety of surveys have been developed to monitor self-reported adherence, there is no standardized instrument that may be used in routine clinical practice. The usefulness of the Patient Medication Adherence Questionnaire (PMAQ) was evaluated in HIV-infected patients on protease inhibitor (PI)-containing regimens., Method: Data from 149 patients were collected. Study participants completed the PMAQ and provided blood samples to measure plasma HIV-1 RNA concentrations and trough plasma levels of PI. Patients were considered adherent if they had a virologic response and/or had an adequate trough plasma level of PI., Results: A close relationship was found between patient reports of adherence during the previous 4 days and objective measures such as HIV RNA level and plasma levels of PI. Motivation with regard to antiretroviral treatment, confidence in personal skills, and an optimistic attitude to life were identified as important determinants of adherence. On the other hand, sociodemographic background, social support, alcohol and illicit drug use, bothersome symptoms, and depression were not associated with a lower medication adherence., Conclusion: Patients' psychological and behavioral factors are central in the acceptance and adherence to antiretroviral therapy. To improve the feasibility and the reproducibility of the PMAQ, we propose a revised form of the PMAQ, focusing on the variables identified as strong predictors of adherence.