From OMIM
Highly active antiretroviral therapy (HAART) has reduced mortality associated with acquired immunodeficiency syndrome (AIDS; see 609423) by at least 70%. Efavirenz is a non-nucleoside reverse transcriptase inhibitor that is frequently prescribed with 2 nucleoside reverse transcriptase inhibitors as initial therapy for human immunodeficiency virus (HIV) infection. However, during the first weeks of therapy, up to half of patients who receive efavirenz experience CNS side effects, including dizziness, insomnia, impaired concentration, somnolence, and abnormal dreams. Severe depression, aggressive behavior, and paranoid or manic reactions may also occur, and such side effects may reflect varying efavirenz plasma concentrations. Plasma clearance of efavirenz appears slower in African Americans than in European Americans, and studies have suggested earlier virologic failure on efavirenz for both African Americans and Hispanics compared with European Americans. Efavirenz is metabolized primarily by hepatic CYP2B6, with some involvement of CYP3A (CYP3A4; 124010) (summary by Haas et al., 2004).  http://www.omim.org/entry/614546