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 may signal mental health problems:
- Feeling sad or hopeless.
- Feeling anxious or restless.
- Having thoughts of hurting yourself (suicide) or have tried to hurt yourself or others.
- Not able to tell the difference between what is true or real and what is false or unreal.
- Not trusting other people.
- Hearing or seeing things that are not real.
Contact your health care provider right away if you have any of the following symptoms that may signal liver problems:
- Yellowing of your skin or the whites of your eyes.
- Dark-colored urine.
- Light-colored bowel movements.
- Loss of appetite for several days or longer.
- Pain in the stomach area (abdominal pain).
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 any of the following symptoms:
Tell your health care provider if you notice any side effects while taking efavirenz.
- Swelling of your face.
- Blisters or skin lesions.
- Peeling of your skin.
- Sores in your mouth.
- Redness or swelling of your eyes.
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.
What is efavirenz?
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.
Efavirenz does not cure HIV/AIDS. People with HIV should stay on continuous HIV treatment as directed by their health care provider and should take steps to avoid passing HIV to others (for example, always using a condom during sex).
What should I tell my health care provider before taking efavirenz?
Before taking efavirenz, tell your health care provider:
- If you are allergic to efavirenz or any other medicines.
- If you have ever had liver problems, including hepatitis B or C infection.
- If you have ever had mental illness.
- If you have ever used drugs or large amounts of alcohol.
- If you have ever had seizures or are taking medicine for seizures.
- If you have any other medical conditions.
- If you are pregnant or plan to become pregnant. Women should not become pregnant while taking efavirenz and for 12 weeks after stopping the drug. 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.
- If you are breastfeeding or plan to breastfeed. Do not breastfeed if you are infected with HIV or are taking efavirenz.
- If you are using hormone-based birth control (such as pills, injections, or implants). Efavirenz may make these forms of birth control less effective. Your health care provider can help you decide how to adjust your birth control while you are taking efavirenz.
- About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Efavirenz may affect the way other medicines or products work, and other medicines and products may affect how efavirenz works. Taking efavirenz together with certain medicines or products may cause serious and/or life-threatening side effects.
How should I take efavirenz?
Efavirenz comes in the following forms and strengths:
- 50-mg and 200-mg capsules (brand name: Sustiva).
- 600-mg tablets (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.)
What should I do if I forget a dose?
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.
What side effects can efavirenz cause?
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:
- Changes in body fat (lipodystrophy).
- Increases in certain fat (cholesterol and triglyceride) levels in the blood (hyperlipidemia).
- Changes in the immune system (immune reconstitution inflammatory syndrome [IRIS]).
- Nervous system symptoms, including dizziness, drowsiness, trouble sleeping, unusual dreams, and trouble concentrating. (These symptoms usually go away within 4 weeks of beginning treatment.)
- Upset stomach, vomiting, and diarrhea.
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. Ask your health care provider or pharmacist for more information on possible side effects of efavirenz. You may also want to read this fact sheet about HIV medicines and side effects.
You may report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088).
How should efavirenz be stored?
- Store efavirenz at room temperature, 68°F to 77°F (20°C to 25°C).
- Keep efavirenz in the container that it came in and keep the container tightly closed. If the container has a small packet of drying agent (called a desiccant), do not remove it. The desiccant protects the medicine from moisture.
- Safely throw away efavirenz that is no longer needed or expired (out of date).
- Keep efavirenz and all medicines out of reach of children.
Where can I find more information about efavirenz?
More information about efavirenz is available:
Last Reviewed: July 3, 2014
Last Updated: July 3, 2014