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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 purposes other than those listed in this medication guide.

Precautions

Instructions

Side-effects

Interactions

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.

Before taking efavirenz, tell your doctor if you are allergic to any drugs, or 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.

If you have any of these conditions, you may not be able to use efavirenz, or you may need a dosage adjustment or special tests during treatment.

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. Tell your doctor if you become pregnant during treatment. Use an effective form of birth control while you are using this medication. Ask your doctor about using a non-hormone method of birth control (such as a condom, diaphragm, spermicide) to prevent pregnancy while taking efavirenz.

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.

If you also take an antacid, take it at least 1 hour before or after taking efavirenz. Do not take antacids at the same time as taking efavirenz.

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.

Avoid using other medicines that make you sleepy (such as cold medicine, pain medication, sleeping pills, muscle relaxers, and medicine for seizures, depression or anxiety). They can add to sleepiness caused by efavirenz.

Taking efavirenz will not prevent you from passing HIV to other people through unprotected sex or sharing of needles. Talk with your doctor about safe methods of preventing HIV transmission during sex, such as using a condom and spermicide. 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.

Symptoms of an efavirenz overdose may include 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 be more likely to occur, such as:

• mild nausea, vomiting, or stomach pain;
• diarrhea or constipation;
• cough;
• blurred vision;
• headache, dizziness, tired feeling;
• trouble concentrating;
• 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).

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

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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:

• sildenafil (Viagra);
• 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), itraconazole (Sporanox), 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), nimodipine (Nimotop), nisoldipine (Sular), or verapamil (Calan, Covera, Isoptin, Verelan);
• other HIV medicines such as amprenavir (Agenerase), indinavir (Crixivan), lopinovir/ritonavir (Kaletra), nevirapine (Viramune), ritonavir (Norvir), or saquinavir (Invirase); or
• seizure medications such as phenytoin (Dilantin) or carbamazepine (Tegretol).

If you are using any of these drugs, you may not be able to use efavirenz, or you may need dosage adjustments or special tests during treatment.

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.

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