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Efavirenz (By mouth)

Efavirenz (ef-a-VYE-renz)

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

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to efavirenz, or if you are pregnant.

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 change your dose or stop using the medicine unless your doctor tells you to.
  • Take this medicine on an empty stomach, preferably at bedtime. Swallow this medicine whole with water. Do not break, crush, or chew the tablets.
  • If you or your child cannot swallow capsules or tablets:
    • You may open the capsule and pour the contents into 1 to 2 teaspoons of soft food (such as applesauce, grape jelly, or yogurt).
    • For babies who cannot eat solid foods yet, you may also mix it with infant formula. Formula must be given through an oral dosing syringe.
    • This mixture must be given within 30 minutes of mixing.
    • After the mixed medicine has been taken, add a small amount of food or formula back to the empty container and gently stir to mix any medicine left in it. 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.
  • Take this medicine at the same time each day and do not miss any doses. Contact your doctor or pharmacist ahead of time when your supply is running low so you do not run out.
  • 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. Atripla® also has efavirenz in it.
  • Some foods and medicines can affect how efavirenz works. Tell your doctor if you are using medicine to treat an infection, an estrogen hormone replacement or birth control pill, birth control implant, medicine to treat hepatitis C, medicine to treat seizures, medicine to treat depression, blood pressure medicine, medicine to lower cholesterol, medicine to treat malaria, medicine that weakens the immune system, pain medicine, or a blood thinner (such as warfarin).
  • Tell your doctor if you take rifampin or voriconazole. Your dose may need to be changed.
  • Alcohol, narcotic pain relievers, or sleeping pills may cause you to feel more lightheaded, dizzy, or faint when used with this medicine. Tell your doctor if you drink alcohol or use pain relievers or sleeping pills.

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.
  • Birth control pills, implants, and other forms of hormonal birth control may not work as well while you are using efavirenz. Use a second form of birth control, such as condoms, a diaphragm, or contraceptive foam, while you take this medicine and for 12 weeks after you stop taking it.
  • 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 or hepatitis B or C, seizures, mental illness, emotional problems, or drug abuse. Tell your doctor about any other medical problems you currently have or had in the past.
  • This medicine may cause the following problems:
    • Changes in mood or behavior
    • Severe liver problems
    • Changes in body fat
    • Rash or other skin problems
  • Your immune system may get stronger when you start taking this 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, use machines, 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
  • Blistering, peeling, or red skin rash
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Seizures
  • Severe depression, anxiety, anger, mood changes, seeing or hearing things that are not there, thoughts of hurting yourself or others

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

  • Dizziness, drowsiness, tiredness
  • Headache
  • Rash or itching
  • 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

Last Updated: 3/28/2016
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