Efavirenz is 1,4-Dihydro-2H-3,1-benzoxazin-2-one substituted at the 4 position by cyclopropylethynyl and trifluoromethyl groups (S configuration) and at the 6 position by chlorine. A non-nucleoside reverse transcriptase inhibitor with activity against HIV, it is used with other antiretrovirals for combination therapy of HIV infection. It has a role as a HIV-1 reverse transcriptase inhibitor and an antiviral drug. It is a benzoxazine, an acetylenic compound, an organochlorine compound, an organofluorine compound and a member of cyclopropanes.