What are the most important things to know about efavirenz?
Efavirenz can cause serious, life-threatening side effects. These include mental health problems, liver problems, and severe skin rash and allergic reactions.
Contact your health care provider right away if you have any of the following symptoms that could be signs of mental health problems:
- Feeling sad or hopeless
- Feeling anxious or restless
- Harming yourself or others or having thoughts about harming yourself (including suicidal thoughts) or others
- Not being 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
- Not being able to move or speak normally
Some people taking efavirenz have had liver problems. People with a history of hepatitis B virus infection (HBV) or hepatitis C virus infection (HCV) or who have elevated results on liver function tests may have an increased risk of developing new or worsening liver problems while taking efavirenz. Liver problems have also occurred in people taking efavirenz who have no history of liver disease. Liver function tests may be done before and during treatment with efavirenz.
Contact your health care provider right away if you have any of the following symptoms that could be signs of liver problems:
- Yellowing of your skin or the whites of your eyes (jaundice)
- Dark-colored urine
- Light-colored bowel movements
- Loss of appetite for several days or longer
- Nausea or vomiting
- Pain, aching, or tenderness on the right side of your stomach/abdominal area
Contact your health care provider right away if you develop a rash while taking efavirenz. Stop taking efavirenz and get medical help right away if you develop a rash with any of the following symptoms:
- General ill feeling
- Extreme tiredness
- Muscle or joint aches
- Blistering or peeling skin
- Blisters or sores in your mouth
- Redness or swelling of the eyes (conjunctivitis)
- Swelling of your face, lips, mouth, tongue, or throat
- Trouble breathing or swallowing
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. Efavirenz is always used in combination with other HIV medicines.
For more information on the use of efavirenz in people with HIV, please refer to the Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV and the Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.
HIV medicines cannot cure HIV/AIDS, but taking HIV medicines 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, do not cut down on, skip, or stop taking them unless your health care provider tells you to.
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 a heart condition.
- If you have ever had a mental health problem.
- If you have ever used street drugs or large amounts of alcohol.
- If you have liver problems, including hepatitis B virus infection (HBV) or hepatitis C virus infection (HCV).
- If you have ever had a seizure or if you take a medicine to help prevent seizures.
- If you have any other medical conditions.
- If you are pregnant or plan to become pregnant. Talk to your health care provider about the risks and benefits of taking efavirenz during pregnancy. For more information on the use of efavirenz during pregnancy, please refer to the Recommendations for the Use of Antiretroviral Drugs During Pregnancy and Interventions to Reduce Perinatal HIV Transmission in the United States.
- If you are breast/chestfeeding or plan to breast/chestfeed. For people with HIV in the United States, the Guideline recommends speaking with your health care provider to discuss options for feeding your baby. People with suppressed viral load have a less than 1% chance of transmitting HIV to their baby via their own milk.
- If you are using hormone-based birth control (such as injections, vaginal rings, implants, a contraceptive patch, or birth control pills). 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. For more information about using birth control and HIV medicines at the same time, view the HIVinfo HIV and Birth Control infographic.
- 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 or products may affect how efavirenz works. Taking efavirenz together with certain medicines or products may cause serious side effects.
How should I take efavirenz?
Efavirenz comes in the following forms and strengths:
- 50-mg, 100-mg, and 200-mg capsules
- 600-mg tablets
Take efavirenz according to your health care provider’s instructions. Do not miss a dose of efavirenz, and do not change your dose or stop taking efavirenz without first talking with your health care provider.
Take efavirenz on an empty stomach, preferably at bedtime. Taking efavirenz at bedtime might help to make some of the side effects less bothersome. Do not break efavirenz tablets. Swallow efavirenz tablets and capsules whole with liquid.
Tell your health care provider if you or your child have trouble swallowing tablets or capsules. Your health care provider may recommend that you open the efavirenz capsule and mix the contents with a small amount of food or infant formula. See the "Instructions for Use" that come with efavirenz capsules for complete instructions on the capsule sprinkle method. Adults and children who take efavirenz using the capsule sprinkle method should not eat for 2 hours after taking a dose of efavirenz.
Always take efavirenz in combination with other HIV medicines.
If you have taken 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 labels for efavirenz capsule and efavirenz tablet (film coated).
What should I do if I forget a dose?
If you miss a dose of efavirenz, take the missed dose as soon as you remember it. 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 may cause side effects. Some side effects of efavirenz can be serious as noted above. Many side effects from HIV medicines, such as nausea or occasional dizziness, are manageable. See the HIVinfo fact sheet on HIV Medicines and Side Effects for more information.
Other possible side effects of efavirenz include:
- Nervous system symptoms, including dizziness, trouble sleeping, unusual dreams, trouble concentrating, drowsiness, and lack of coordination or difficulty with balance.
- Seizures, which are more likely to happen if you have had seizures in the past.
- Changes in your immune system (called immune reconstitution inflammatory syndrome or IRIS). IRIS is a condition that sometimes occurs when the immune system begins to recover after treatment with an HIV medicine. As the immune system gets stronger, it may have an increased response to a previously hidden infection.
- Changes in body fat (lipodystrophy syndrome).
- Increases in the levels of certain fats (cholesterol and triglycerides) in the blood (hyperlipidemia).
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 labels or package inserts for efavirenz capsule and efavirenz tablet (film coated) or talk to your health care provider or pharmacist.
You can report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088) or online.
How should efavirenz be stored?
- Store efavirenz capsule and tablets 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.
- Do not use efavirenz if the original seal over the container opening is broken or missing.
- Throw away efavirenz that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
- Keep efavirenz and all medicines out of reach of children.
Where can I find more information about efavirenz?
- For more information on the use of efavirenz in people with HIV, please refer to the Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV and the Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection.
- This Patient Version drug summary is based on the following FDA label(s): Capsule; Tablet (film coated). The Patient Information section and Instructions For Use include information for people taking efavirenz.
- The American Hospital Formulary Service (AHFS) Patient Medication Information for efavirenz available from MedlinePlus.
- Efavirenz-related research studies, from ClinicalTrials.gov. (The ClinicalTrials.gov search can be modified so that you can get results that better match your interests. To learn more about the ClinicalTrials.gov search features, please see How to Search.)
- A list of FDA-approved HIV medicines, from HIVinfo.
Sustiva brand products are discontinued. For information on generic efavirenz products, please refer to the generic drug labels.
Last Reviewed: May 1, 2023