High Prevalence of Subtherapeutic Plasma Concentrations of Efavirenz in Children

• DOI: 10.1097/qai.0b013e31805c9d52
• Publication Date: 2007-04-06T08:07:03Z
• Authors: Yuan Ren; James J C Nuttall; Claire Egbers; Brian S Eley; Tammy M Meyers; Peter J Smith; Gary Maartens; Helen M McIlleron
• Keywords: Efavirenz; Cmin; Therapeutic Drug Monitoring; Trough Concentration

Objective: Efavirenz-containing regimens using concentration-controlled dosing have been shown to provide potent antiretroviral activity in children. In many settings, is not available. this study, efavirenz plasma concentrations were evaluated South African HIV-infected children receiving efavirenz-based treatment. Methods: Three consecutive blood samples drawn between 12 and 24 hours after 15 the recommended daily doses of efavirenz. Validated liquid chromatography tandem mass spectrometry methods used determine levels The trough concentration (Cmin) was estimated by extrapolation log-linear regression line 3 versus time points hours. Results: Cmin <1 mg/L 6 (40%) 5 with detectable viral loads had low concentrations. Marked bimodality observed. Conclusions: Our findings, together those previous studies, indicate that dosed according current guidelines do achieve adequate exposure. Because are associated rapid emergence efavirenz-resistant mutations treatment failure, should be re-evaluated, especially developing countries, where therapeutic drug monitoring seldom