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 transcript ase, is a promising addition to the antiretroviral arm amentarium. Efavirenz levels and HIV-1 RNA levels were measured in ccrebros pinal fluid (CSF) and plasma of 10 HIV-1-infected patients taking efavirenz , 600 mg daily, in combination with other antiretroviral medications. Efavi renz 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-pl asma ratio was 0.61% (range, 0.26%-0.99%). CSF HIV-1 RNA levels were ascert ained in 9 of the patients; all were <400 copies/mL after a mean of 26 week s on therapy. Eight of the 9 patients had no detectable virus in plasma. Th ese results indicate that efavirenz is present in the CSF at low levels and is effective in suppressing CSF viral levels when used in combination ther apy.