Efavirenz

(CC) Image: David E. Volk
Efavirenz, a non-nucleoside reverse transcriptase inhibitor.

Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and is used as part of highly active antiretroviral therapy (HAART) for the treatment HIV-1. It is a synthetic purine derivative similar to zidovudine, zalcitabine, and stavudine. Efavirenz and lamivudine with either zidovudine or tenofovir is the preferred NNRTI-based regimen for HIV infections not previously treated. It is also used in combination with other anti-HIV drugs in expanded prophylactic treatment upon possible HIV exposure. It is sold under the brand names Sustiva® and Stocrin®. Fetal harm, central nervous system symptoms and psychiatric symptoms have been reported with this drug.

Its IUPAC chemical name is (4S)-6-chloro-4-(2-cyclopropylethynyl)-4-(trifluoromethyl)-1H-3,1-benzoxazin-2-one and its chemical formula is C₁₄H₉ClF₃NO₂ (MW = ).

Drug interactions

St. John's Wort and saquinavir decrease the antiretroviral effects of efavirenz, and efavirenz decreases the levels and/or effects of atazanavir, clarithromycin, cyclosporin, indinavir, methadone and voriconazole.

Efavirenz may increase the toxicity of ergot derivatives, including dihydroergotamine, dihydroergotoxine, ergotamine, methylergonovine and methysergide and some statin drugs, including atorvastatin, lovastatin and simavstatin. An increased risk of cardiotoxicity and arrhythmias occurs when efavirenz is taken with astemizole or cisapride or terfenadine. Increased toxicity of benzodiazepine is noted when taken with alprazolam, midazolam or triazolam.

External Links

• Efavirenz - FDA approved drug information (drug label) from DailyMed (U.S. National Library of Medicine).
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