Usefulness of therapeutic drug monitoring of antiretrovirals in routine clinical practice.

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.

Acute liver enzyme elevations in HIV-1-infected patients.

BACKGROUND: Acute liver enzyme elevations (ALEE) have been associated with a first-line highly active antiretroviral therapy (HAART) and/or viral hepatitis coinfections in HIV-infected patients. By comparison, the frequency and the risk factors of ALEE in untreated patients and in patients treated with several antiretroviral regimens need to be assessed. PURPOSE: To describe the long-term frequency and the characteristics of ALEE in antiretroviral treated and untreated patients and to define risk factors for ALEE in a retrospective cohort of HIV-1-infected patients. METHOD: An HIV-infected cohort was retrospectively examined. ALEE was defined as levels of alanine amino transferase and/or alkaline phosphatase rising to at least 2.5 times above baseline values. Hazard ratios (HR) for ALEE were estimated using an extension of the Cox proportional model taking into account recurrent events. RESULTS: Out of 239 assessable patients, 12 (5%) were coinfected with hepatitis B virus (HBV) and 34 (14.2%) with hepatitis C virus (HCV). The incidence rate of ALEE was 9.9/100 patients-year and the cumulative incidence was 20.9%. HCV genotype 3 tended to give a higher risk of ALEE. Independent factors for developing ALEE in multivariate logistic regression were HBV (HR = 4.0) and HCV (HR = 3.4) coinfections, antiretroviral therapy (HR = 2.6), CDC stage C (HR = 2.5), and high alkaline phosphatase baseline values (HR = 1.7). CONCLUSION: The occurrence of ALEE is influenced more by the past medical history and the clinical background of the patients than by antiretroviral therapy. These patient-linked variables must be taken into account to avoid unwarranted treatment withdrawal.