Efavirenz can cause serious, life-threatening side effects. These include serious mental health problems, liver problems, and severe rash.
Contact your health care provider right away if you have any of the following symptoms that could be signs of mental health problems:
Contact your health care provider right away if you have any of the following symptoms that could be signs of liver problems:
Skin rash is common with taking efavirenz and usually goes away within 4 weeks of beginning treatment, but it can also be severe. Contact your health care provider right away if you develop a rash—with or without itching—with any of the following symptoms:
Tell your health care provider if you notice any side effects while taking efavirenz.
Women should not become pregnant while taking efavirenz and for 12 weeks after stopping the medicine. Serious birth defects have been seen in the babies of animals and women treated with efavirenz during pregnancy. Whether efavirenz caused the birth defects is unknown.
While taking efavirenz, it is important to keep all of your appointments with your health care provider.
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.
Before taking efavirenz, tell your health care provider:
Efavirenz comes in the following forms and strengths, under the brand name Sustiva:
Take efavirenz according to your health care provider’s instructions.
Take efavirenz on an empty stomach and without food, preferably at bedtime. Swallow efavirenz with liquid.
Tell your health care provider if you or your child is unable to swallow tablets or capsules. Your health care provider can give you instructions on how to mix the contents of efavirenz capsules with soft food (or infant formula) to make the medicine easier to take.
Always take efavirenz in combination with other HIV medicines.
If you take too much efavirenz, contact your health care provider or local poison control center (1-800-222-1222) right away, or go to the nearest hospital emergency room.
For more information on how to take efavirenz, see the FDA drug label from DailyMed. (DailyMed is a federal website that includes the most recent drug labels submitted to FDA.)
If you miss a dose of efavirenz, take the missed dose right away. But if it is almost time for your next dose, skip the missed dose and just take your next dose at the regular time. Do not take two doses at the same time to make up for a missed dose.
Efavirenz can cause serious, life-threatening side effects. These include serious mental health problems, liver problems, and severe rash. (See the WARNING above.)
Other possible side effects of efavirenz include:
Tell your health care provider if you have any side effect that bothers you or that does not go away.
These are not all the possible side effects of efavirenz. To learn more about possible side effects of efavirenz, read the drug label or package insert or talk to your health care provider or pharmacist.
The AIDSinfo fact sheet on HIV Medicines and Side Effects also includes information that may apply to efavirenz.
You can also report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088) or online at https://www.accessdata.fda.gov/scripts/medwatch/.
More information about efavirenz is available:
Last Reviewed: June 24, 2015