Health Library

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 at bedtime.
• Swallow the capsule or tablet whole with water. Do not break, crush, or chew the tablet.
• If you or your child are unable to swallow the capsule whole:
  • Wash and dry your hands well.
  • Gather a teaspoon, a spoon for stirring, and a small clean container such as a small cup or bowl.
  • Open the capsule and pour the contents into 1 to 2 teaspoons of soft food (including applesauce, grape jelly, or yogurt) in the container. You may instead mix the medicine into infant formula in the container.
  • Using the small spoon, gently mix the capsule contents and food together. It will not completely dissolve. Mixture will look grainy but should not be lumpy.
  • The mixture should be taken or given within 30 minutes. Use the small spoon to give or take the mixture. If you use the oral syringe, place the tip into the container. Slowly pull back on the plunger and draw up the mixture.
  • Place the tip of the syringe in your baby's mouth along the inner cheek. Slowly push on the plunger to give your baby all of the mixture.
  • Add another 2 teaspoons of the soft food into the empty container and gently stir with the small spoon to mix any remaining capsule contents. Give or take the mixture with the spoon or syringe as above.
  • 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 use this medicine together with elbasvir/grazoprevir. Do not take other medicines that contain efavirenz (including efavirenz/emtricitabine/tenofovir).
• Some medicines can affect how efavirenz works. Tell your doctor if you are using any of the following:
  • Artemether/lumafentrine, atorvastatin, atovaquone/proguanil, boceprevir, cyclosporine, methadone, pibrentasvir/glecaprevir, pravastatin, praziquantel, rifabutin, rifampin, simeprevir, simvastatin, sirolimus, tacrolimus, velpatasvir/sofosbuvir, velpatasvir/sofosbuvir/voxilaprevir
  • Birth control pills (including ethinyl estradiol/norgestimate)
  • Blood pressure medicine (including diltiazem, felodipine, nicardipine, nifedipine, verapamil)
  • Blood thinner (including warfarin)
  • Medicine to treat depression (including bupropion, sertraline)
  • Medicine to treat infection (including clarithromycin, itraconazole, ketoconazole, posaconazole, voriconazole)
  • Other medicine to treat HIV (including atazanavir, fosamprenavir, indinavir, lopinavir/ritonavir, maraviroc, ritonavir, saquinavir)
  • Seizure medicine (including carbamazepine, phenobarbital, phenytoin)
• Do not drink alcohol while you are using this medicine.
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

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. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting this medicine. Birth control pills may not work as well to prevent pregnancy when used with this medicine. Use another form of birth control (including condoms or spermicide) along with your pills to keep from getting pregnant during treatment and for 12 weeks after the last dose.
• Do not breastfeed. You can spread HIV or AIDS to your baby through your breast milk.
• Tell your doctor if you have liver disease (including hepatitis B or C), heart disease, or history of seizures, depression, mental illness, or alcohol or drug abuse.
• This medicine may cause the following problems:
  • Heart rhythm problems, including QT prolongation
  • Unusual changes in mood or behavior
  • 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.
• Always practice safe sex, even if your partner also has HIV. If you stop taking this medicine or do not take it as prescribed, you may spread HIV to others. Do not reuse or 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
• Behavior or mood changes, depression, seeing or hearing things that are not there
• Blistering, peeling, red skin rash
• Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
• Fainting, dizziness, lightheadedness
• Fast, pounding, or uneven heartbeat
• Seizures

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

• Drowsiness, tiredness
• Headache
• Trouble sleeping or concentrating
• 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

Last Updated: 9/6/2024