Cerebrospinal Fluid Human Immunodeficiency Virus Type 1 (HIV-1) Suppression and Efavirenz Drug Concentrations in HIV-1—Infected Patients Receiving Combination Therapy

Efavirenz, a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase, is a promising addition to the antiretroviral armamentarium. Efavirenz levels and HIV-1 RNA levels were measured in cerebrospinal fluid (CSF) and plasma of 10 HIV-1-infected patients taking efavirenz, 600 mg daily, in combination with other antiretroviral medications. Efavirenz was detected in the CSF at a mean concentration of 35.1 nM (range, 6.6–58.9 nM), which was above the IC95 for wild-type HIV-1. The mean CSF-to-plasma ratio was 0.61% (range, 0.26%–0.99%). CSF HIV-1 RNA levels were ascertained in 9 of the patients; all were