What is efavirenz?

Efavirenz is an antiviral medication that prevents human immunodeficiency virus (HIV) cells from multiplying in your body.

Efavirenz is used to treat HIV, which causes the acquired immunodeficiency syndrome (AIDS). Efavirenz is not a cure for HIV or AIDS.

Efavirenz may also be used for other purposes not listed in this medication guide.

Precautions

Do not use this medication if you are allergic to efavirenz, or if you are using any of the following drugs:

  • astemizole (Hismanal);
  • bepridil (Vascor);
  • cisapride (Propulsid);
  • midazolam (Versed) or triazolam (Halcion);
  • pimozide (Orap);
  • voriconazole (Vfend); or
  • ergot medicine such as ergotamine (Ergomar, Ergostat, Cafergot, Ercaf, Wigraine), dihydroergotamine (D.H.E. 45, Migranal Nasal Spray), ergonovine (Ergotrate), or methylergonovine (Methergine).

Using any of these medicines while you are taking efavirenz can cause serious medical problems or death.

If you have certain conditions, you may need a dose adjustment or special tests to safely take efavirenz. Before you take efavirenz, tell your doctor if you have:

  • liver disease (including hepatitis B or C);
  • high cholesterol or triglycerides; or
  • if you have ever taken delavirdine (Rescriptor) or nevirapine (Viramune) and they were not effective in treating your condition.

FDA pregnancy category D. This medication can cause harm to an unborn baby. Do not use efavirenz without your doctor’s consent if you are pregnant. Use two forms of birth control, including a barrier form (such as a condom or diaphragm with spermicide gel) while you are taking efavirenz, and for at least 12 weeks after your treatment ends. Tell your doctor if you become pregnant during treatment.

HIV can be passed to the baby if the mother is not properly treated during pregnancy. Take all of your HIV medicines as directed to control your infection while you are pregnant.

Your name may need to be listed on an antiviral pregnancy registry when you start using efavirenz. The purpose of this registry is to track the outcome of the pregnancy and delivery to evaluate whether efavirenz had any effect on the baby.

You should not breast-feed while you are using efavirenz. Women with HIV or AIDS should not breast-feed at all. Even if your baby is born without HIV, you may still pass the virus to the baby in your breast milk.

Efavirenz can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Avoid drinking alcohol. It can increase some of the side effects of efavirenz.

Cold or allergy medicine, sedatives, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures, depression or anxiety can add to sleepiness caused by efavirenz. Tell your doctor if you regularly use any of these medicines.

Avoid having unprotected sex or sharing needles, razors, or toothbrushes. Taking this medication will not prevent you from passing HIV to other people. Talk with your doctor about safe methods of preventing HIV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

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Instructions

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose can cause confusion, lack of balance or coordination, severe mood or behavior changes, or thoughts of suicide.

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Efavirenz may cause serious psychiatric symptoms including confusion, severe depression, suicidal thoughts, aggression, extreme fear, hallucinations, or unusual behavior. Contact your doctor at once if you have any of these side effects, even if you have had them before.

Call your doctor at once if you have any of these serious side effects:

  • fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;
  • nausea, stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • fever, chills, body aches, flu symptoms; or
  • any other signs of new infection.

Less serious side effects may include:

  • mild nausea, vomiting, or stomach pain, diarrhea or constipation;
  • cough;
  • blurred vision;
  • headache, dizziness, tired feeling;
  • trouble concentrating, problems with balance or coordination;
  • muscle or joint pain;
  • sleep problems (insomnia), unusual dreams; or
  • changes in the shape or location of body fat (especially in your arms, legs, face, neck, breasts, and waist).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

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Interactions

There are many other medicines that can interact with efavirenz, or make it less effective. Before taking efavirenz, tell your doctor if you are using any of the following drugs:

  • itraconazole (Sporanox);
  • St. John's wort;
  • a blood thinner such as warfarin (Coumadin);
  • a cholesterol medication such as Lipitor or Zocor;
  • an antibiotic such as clarithromycin (Biaxin), rifabutin (Mycobutin), or rifampin (Rifadin, Rifater, Rifamate, Rimactane);
  • heart or blood pressure medications such as amlodipine (Norvasc), diltiazem (Tiazac, Cartia, Cardizem), felodipine (Plendil), nicardipine (Cardene), nifedipine (Procardia, Adalat), or verapamil (Calan, Covera, Isoptin, Verelan);
  • other HIV medicines such as amprenavir (Agenerase), indinavir (Crixivan), lopinavir/ritonavir (Kaletra), nevirapine (Viramune), ritonavir (Norvir), or saquinavir (Invirase); or
  • seizure medications such as phenytoin (Dilantin) or carbamazepine (Tegretol).

This list is not complete and there are other drugs that can interact with efavirenz. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.

Other Names

Sustiva and efavirenz

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Disclaimer

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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