Efavirenz is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV infection in adults and in children 3 months of age and older who weigh at least 7 pounds 12 ounces (3.5 kilograms). Efavirenz is always used in combination with other HIV medicines.
Efavirenz belongs to a class (group) of HIV drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs attach to and block an HIV enzyme called reverse transcriptase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking reverse transcriptase, NNRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body.
HIV medicines can’t cure HIV/AIDS, but taking a combination of HIV medicines (called an HIV regimen) every day helps people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission. If you are taking HIV medicines, including efavirenz, don’t cut down on, skip, or stop taking them unless your health care provider tells you to.