EFV Pharmacokinetics & Pharmacogenomics in Older HIV-infected Patients

"HIV-infected subjects currently receiving efavirenz (EFV) containing antiretroviral therapy (ART) will be asked to provide plasma samples. In addition to blood samples for determination of EFV concentrations, we will collect whole blood samples for functional Single Nucleotide Polymorphism (SNP) discovery within known candidate genes of interest in drug metabolism and transport.~Subjects will be at steady state for efavirenz when blood samples are collected. EFV is usually taken during the evening hours. The study consists of 2 blood draws at 12 and 18 hours post EFV dose. At the first blood draw, venous blood will be obtained by venous puncture for plasma concentrations of EFV and pharmacogenetics. At 18 hours post EFV dose , a second blood draw by venous puncture will be obtained for EFV plasma concentrations.~Demographics and clinical parameters will be collected at the time of the first visit, Neuropsychological tests and questionnaires completed as well."