Efavirenz (By mouth)


Efavirenz (ef-a-VYE-renz)
Used with other medicines to treat human immunodeficiency virus (HIV) infection. HIV causes acquired immune deficiency syndrome (AIDS). Efavirenz does not cure HIV or AIDS, but it may slow the worsening of the disease.

Brand Name(s)

There may be other brand names for this medicine.


When This Medicine Should Not Be Used

You should not use this medicine if you have had an allergic reaction to efavirenz, or if you are pregnant. You should not use this medicine if you are also using St. John's wort, astemizole (Hismanal®), bepridil (Vascor®), cisapride (Propulsid®), midazolam (Versed®), pimozide (Orap®), triazolam (Halcion®), voriconazole (Vfend®), or ergot medicines (such as dihydroergotamine, ergonovine, ergotamine, methylergonovine, Bellergal-S®, Cafergot®, DHE 45®, Ergostat®, Sansert®, or Wigraine®).

How to Use This Medicine

Capsule, Tablet
  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to. Efavirenz is used with other medicines to treat HIV infection. Make sure you take all of your medicines as your doctor has prescribed.
  • Do not change or stop using this medicine without checking with your doctor first. When your supply of this medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of this medicine.
  • Take this medicine on an empty stomach, preferably at bedtime. Swallow this medicine with water. Take this medicine at the same time each day.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
If a dose is missed:
  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine after you have finished your treatment. You will also need to throw away old medicine after the expiration date has passed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
  • There are many other drugs that may interact with efavirenz. Using these drugs can cause problems that are serious, even life-threatening. Make sure your doctor knows about all other medicines you are using. Tell your doctor if you change a dose of another medicine, or stop taking another medicine. Your dose of efavirenz may need to be changed also.
  • Do not take other medicines to treat HIV or AIDS (such as Atripla®) or St. John's wort while you are being treated with this medicine, unless your doctor says it is okay.
  • Make sure your doctor knows if you are using medicines to treat an infection (such as clarithromycin, rifabutin, rifampin, Biaxin®, Mycobutin®, Rifadin®, Rifamate®, or Rifater®), an estrogen hormone replacement (such as ethinyl estradiol, Estinyl®), a blood thinner (such as warfarin, Coumadin®), or birth control pills. Tell your doctor if you are also using other medicines to treat HIV/AIDS (such as amprenavir, atazanavir, fosamprenavir, indinavir, lopinavir, maraviroc, ritonavir, saquinavir, Agenerase®, Crixivan®, Fortovase®, Invirase®, Kaletra®, Lexiva®, Norvir®, or Reyataz®).
  • Make sure your doctor knows if you are also using medicine to treat seizures (such as carbamazepine, phenobarbital, phenytoin, Carbatrol®, Dilantin®, or Tegretol®), fungus infections (such as itraconazole, ketoconazole, posaconazole, Nizoral®, Noxafil®, or Sporanox®), or depression (such as sertraline, Zoloft®). Tell your doctor if you are also using certain blood pressure medicines (such as diltiazem, felodipine, nicardipine, nifedipine, verapamil, Adalat®, Calan®, Cardene®, Cardizem®, Covera HS®, Isoptin SR®, Plendil®, Procardia®, Tiazac®, or Verelan®), medicine to lower cholesterol (such as atorvastatin, pravastatin, simvastatin, Lipitor®, Pravachol®, or Zocor®), medicine that weakens the immune system (such as cyclosporine, sirolimus, tacrolimus, Gengraf®, Neoral®, Protopic®, Rapamune®, or Sandimmune®), or pain medicine (such as methadone, Dolophine®).
  • Tell your doctor if you are using any medicines that make you sleepy. These include sleeping pills, cold and allergy medicine, narcotic pain relievers, and sedatives.
  • Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine

  • Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. You should not become pregnant while you are taking this medicine and for 12 weeks after stopping it. If you think you have become pregnant while using the medicine, tell your doctor right away. Your doctor may want you to join a pregnancy registry for patients taking an anti-HIV medicine.
  • You should not breast feed if you have HIV or AIDS, because you may give the infection to your baby through your breast milk.
  • Tell your doctor if you have a history of liver disease or hepatitis B or C. Make sure your doctor knows if you have a history of seizures, mental illness, emotional problems, or drug abuse. Tell your doctor if you are currently using alcohol. Make sure your doctor knows about any other medical problems you currently have, or have had in the past.
  • This medicine may increase your risk of having serious mental or behavioral problems. Tell your doctor if you or your child develop any mood changes, strange thoughts, or any unusual behavior while you are using this medicine.
  • Stop using this medicine and check with your doctor right away if you or your child have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.
  • When you start taking HIV medicines, your immune system may get stronger. If you or your child have infections that are hidden in your body, such as pneumonia or tuberculosis, you may notice new symptoms when your body tries to fight them. If this occurs, be sure to tell your doctor.
  • This medicine will not keep you from giving HIV to your partner during sex. Make sure you understand and practice safe sex, even if your partner also has HIV. Do not share needles with anyone.
  • Birth control pills may not work as well while you are using efavirenz. Use an additional form of birth control along with your pills while you are taking this medicine and for 12 weeks after stopping it to keep from getting pregnant. Other forms include condoms, diaphragms, or contraceptive foams or jellies.
  • This medicine may cause you or your child to have excess body fat. Tell your doctor if you or your child notice changes in your body shape, such as an increased amount of fat in the upper back and neck, or around the chest and stomach area. You might also lose fat from the legs, arms, and face.
  • This medicine may make you or your child dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.
  • Check with your doctor right away if you or your child develop a skin rash; blistering, peeling, or loosening of the skin; red skin lesions; sores or ulcers on the skin; or fever or chills while you or your child are using this medicine.
  • Your doctor will need to check your progress at regular visits while you are using this medicine. Be sure to keep all appointments. Blood tests may be needed to check for unwanted effects.
  • Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.

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.
  • Confusion, trouble thinking clearly, or hallucinations (seeing or hearing things that are not there).
  • Dark-colored urine or pale stools.
  • Fast or pounding heartbeat.
  • Fever or cough.
  • Lightheadedness or fainting.
  • Seizures or tremors.
  • Severe depression (sadness), anxiety, nervousness, mood changes, problems dealing with anger, or thoughts of hurting yourself or others.
  • Sudden and severe stomach pain, nausea, or vomiting.
  • Yellowing of your skin or the whites of your eyes.
If you notice these less serious side effects, talk with your doctor:
  • Diarrhea, stomach pain, or upset stomach.
  • Dizziness or headache.
  • Gaining weight around your neck, upper back, breast, face, or waist.
  • Joint or muscle pain.
  • Mild skin rash or itching.
  • Problems with balance or walking.
  • Sleepiness or unusual drowsiness.
  • Tiredness.
  • Trouble with sleeping or concentrating, strange dreams.

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
Review Date: 2011-02-04 Reviewed By: Keywords: ,
Adam Data Copyright The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only--they do not constitute endorsements of those other sites. © 1997- 2010 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

For information 410.787.4000

© 2015 UM Baltimore Washington Medical Center.  All rights reserved.

301 Hospital Drive, Glen Burnie, MD 21061 | 410-787-4000 | TTY 410-787-4498