Efavirenz (By mouth)


Efavirenz (ef-a-VYE-renz)

Treats HIV infection. HIV causes AIDS. This medicine does not cure HIV or AIDS, but combinations of drugs may slow the progress of the disease.

Brand Name(s)


When This Medicine Should Not Be Used

How to Use This Medicine

Capsule, Tablet

  • Your doctor will tell you how much medicine to use. Do not use more than directed.
  • Take all other medicines your doctor has prescribed as part of your combination treatment.
  • Do not stop using this medicine without talking to your doctor first. If you stop the medicine, even for a short time, the virus may become harder to treat. Contact your doctor or pharmacist when your supply is running low so you do not run out.
  • Take this medicine on an empty stomach, preferably at bedtime. Swallow the capsule or tablet whole with water. Do not break, crush, or chew the tablet.
  • If you cannot swallow the capsule whole:
    • You may open the capsule and pour the contents into 1 to 2 teaspoons of soft food (such as applesauce, grape jelly, or yogurt). You may also mix the medicine into an infant's formula.
    • Swallow the mixture within 30 minutes. Give the formula/medicine mixture with an oral dosing syringe.
    • After you swallow the mixture, add a small amount of food (or formula) into the empty container and gently stir. Swallow this mixture, too, to make sure you get all of the medicine that was in the capsule.
    • Do not eat anything else for 2 hours after taking this medicine mixed with food or formula.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Do not take Atripla® while you are being treated with this medicine, unless your doctor tells you to. Atripla® also has efavirenz in it.
  • The list below includes some of the medicines that can interact with efavirenz. There are other drugs not listed. Make sure your doctor knows all of the medicines you use.
    • Artemether/lumefantrine, atorvastatin, atovaquone/proguanil, boceprevir, bupropion, carbamazepine, clarithromycin, cyclosporine, itraconazole, ketoconazole, methadone, phenobarbital, phenytoin, posaconazole, pravastatin, rifabutin, rifampin, sertraline, simeprevir, simvastatin, sirolimus, tacrolimus, or voriconazole
    • Birth control pill or implant
    • Blood pressure medicine
    • Blood thinner (including warfarin)
  • Alcohol, narcotic pain medicine, sleeping pills, and similar medicines may cause you to feel more lightheaded, dizzy, or faint when used together with this medicine.

Warnings While Using This Medicine

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant. Use 2 forms of birth control during your treatment time and for at least 12 weeks after your last dose. Birth control pills may not work while you are using efavirenz, so do not use a hormone method as a form of birth control. Use a barrier method plus another type. Talk with your doctor about what choice is best for you.
  • Do not breastfeed. You can spread HIV or AIDS to your baby through your breast milk.
  • Tell your doctor if you have a history of liver disease (including hepatitis B or C), seizures, mental illness, or drug abuse.
  • This medicine may cause the following problems:
    • Severe liver problems
    • Severe skin rash
    • Increased cholesterol level
    • Changes in body fat
  • Your immune system may get stronger when you start taking an HIV medicine. This could cause a hidden infection in your body to become active. Tell your doctor right away if you notice any changes in your health.
  • This medicine may make you dizzy or drowsy. Do not drive or do anything that could be dangerous until you know how this medicine affects you.
  • This medicine will not keep you from giving HIV to others. Always practice safe sex, even if your partner also has HIV. Do not share needles or other items that may have blood or body fluids on them.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Anxiety, anger, aggression, severe depression, seeing or hearing things that are not there, or thoughts of hurting yourself or others
  • Behavior or mood changes , paranoid or manic behavior
  • Blistering, peeling, or red skin rash
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Seizures

If you notice these less serious side effects, talk with your doctor:

  • Dizziness, tiredness
  • Headache
  • Trouble sleeping or concentrating, strange dreams
  • Weight gain around your neck, upper back, breast, face, or waist

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 9/14/2016

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