8-hydroxyEfavirenz is a major oxidative metabolite of the non-nucleoside reverse transcriptase inhibitor efavirenz . 8-hydroxyEfavirenz is formed when efavirenz is metabolized by the cytochrome P450 (CYP) isoform CYP2B6. It induces apoptosis in rat primary hippocampal neurons and loss of dendritic spines in rat primary hippocampal neuronal cultures when used at a concentration of 0.01 μM.