Efavirenz

Efavirenz is a prescription medication used to treat infection with human immunodeficiency virus (HIV). Efavirenz must be taken with other anti-HIV medicines. Efavirenz belongs to a group of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), which work by stopping the virus from replicating, lowering the amount in the blood.   

Efavirenz is a medicine used in combination with other medicines to help treat infection with human immunodeficiency virus (HIV), the virus that causes AIDS (acquired immune deficiency syndrome).

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Efavirenz may be found in some form under the following brand names:

• Atripla

• Sustiva

Serious psychiatric problems. A small number of patients experience severe depression, strange thoughts, or angry behavior while taking efavirenz. Some patients have thoughts of suicide and a few have actually committed suicide. These problems tend to occur more often in patients who have had mental illness. Contact your doctor right away if you think you are having these psychiatric symptoms, so your doctor can decide if you should continue to take efavirenz.

Common side effects. Many patients have dizziness, trouble sleeping, drowsiness, trouble concentrating, and/or unusual dreams during treatment with efavirenz. These side effects may be reduced if you take efavirenz at bedtime on an empty stomach. They also tend to go away after you have taken the medicine for a few weeks. If you have these common side effects, such as dizziness, it does not mean that you will also have serious psychiatric problems, such as severe depression, strange thoughts, or angry behavior. Tell your doctor right away if any of these side effects continue or if they bother you. It is possible that these symptoms may be more severe if efavirenz is used with alcohol or mood altering (street) drugs.

If you are dizzy, have trouble concentrating, or are drowsy, avoid activities that may be dangerous, such as driving or operating machinery.

Rash is common. Rashes usually go away without any change in treatment. In a small number of patients, rash may be serious. If you develop a rash, call your doctor right away. Rash may be a serious problem in some children. Tell your child’s doctor right away if you notice rash or any other side effects while your child is taking efavirenz.

Other common side effects include tiredness, upset stomach, vomiting, and diarrhea. Some patients taking efavirenz have experienced increased levels of lipids (cholesterol and triglycerides) in the blood.

Changes in body fat. Changes in body fat develop in some patients taking anti-HIV medicine. These changes may include an increased amount of fat in the upper back and neck (“buffalo hump”), in the breasts, and around the trunk. Loss of fat from the legs, arms, and face may also happen. The cause and long-term health effects of these fat changes are not known.

Liver problems. Some patients taking efavirenz have experienced serious liver problems including liver failure resulting in transplantation or death. Most of these serious side effects occurred in patients with a chronic liver disease such as hepatitis infection, but there have also been a few reports in patients without any existing liver disease.

Tell your doctor or healthcare provider if you notice any side effects while taking efavirenz.

Contact your doctor before stopping efavirenz because of side effects or for any other reason.

This is not a complete list of side effects possible with efavirenz. Ask your doctor or pharmacist for a more complete list of side effects of efavirenz and all the medicines you will take.

Efavirenz may change the effect of other medicines, including ones for HIV, and cause serious side effects. Your doctor may change your other medicines or change their doses. Other medicines, including herbal products, may affect efavirenz. For this reason, it is very important to:

• let all your doctors and pharmacists know that you take efavirenz.
• tell your doctors and pharmacists about all medicines you take. This includes those you buy over-the-counter and herbal or natural remedies.

Bring all your prescription and nonprescription medicines as well as any herbal remedies that you are taking when you see a doctor, or make a list of their names, how much you take, and how often you take them. This will give your doctor a complete picture of the medicines you use. Then he or she can decide the best approach for your situation.

Taking efavirenz with St. John’s wort (Hypericum perforatum), an herbal product sold as a dietary supplement, or products containing St. John’s wort is not recommended. Talk with your doctor if you are taking or are planning to take St. John’s wort. Taking St. John’s wort may decrease efavirenz levels and lead to increased viral load and possible resistance to efavirenz or cross-resistance to other anti-HIV drugs.

MEDICINES YOU SHOULD NOT TAKE WITH EFAVIRENZ:

The following medicines may cause serious and life-threatening side effects when taken with efavirenz. You should not take any of these medicines while taking efavirenz:

• Vascor (bepridil)
• Propulsid (cisapride)
• Versed (midazolam)
• Orap (pimozide)
• Halcion (triazolam)
• Ergot medications (for example, Wigraine and Cafergot)

Do not take Atripla with this medication, because Atripla also contains efavirenz.

The following medicines may need to be replaced with another medicine when taken with efavirenz:

• Fortovase, Invirase (saquinavir)
• Macrolide antibiotics such as Biaxin (clarithromycin)
• Carbatrol, Tegretol (carbamazepine)
• Noxafil (posaconazole)
• Sporanox (itraconazole)
• Reyataz (atazanavir sulfate), if this is not the first time you are receiving treatment for your HIV infection
• Antimalarials such as artemether/lumefantrine

The following medicines may require a change in the dose of either efavirenz or the other medicine:

• Calcium channel blockers such as Cardizem or Tiazac (diltiazem), Covera HS or Isoptin SR (verapamil), and others.
• The cholesterol-lowering medicines Lipitor (atorvastatin), Pravachol (pravastatin sodium), and Zocor (simvastatin).
• Crixivan (indinavir)
• Kaletra (lopinavir/ritonavir)
• Methadone
• Mycobutin (rifabutin)
• Reyataz (atazanavir sulfate). If you are taking efavirenz and Reyataz, you should also be taking Norvir (ritonavir).
• Rifadin (rifampin) or the rifampin-containing medicines Rifamate and Rifater.
• Selzentry (maraviroc)
• Vfend (voriconazole) and efavirenz must not be taken together at standard doses. Some doses of voriconazole can be taken at the same time as a lower dose of efavirenz, but you must check with your doctor first.
• Zoloft (sertraline)
• Wellbutrin, Wellbutrin SR, Wellbutrin XL, or Zyban (bupropion)
• The immunosuppressant medicines cyclosporine (Gengraf, Neoral, Sandimmune, and others), Prograf (tacrolimus), or Rapamune (sirolimus).

These are not all the medicines that may cause problems if you take efavirenz. Be sure to tell your doctor about all medicines that you take.

Do not take efavirenz if you are allergic to this medication or to any of the inactive ingredients. 

• Women should not become pregnant while taking efavirenz and for 12 weeks after stopping it. Serious birth defects have been seen in the offspring of animals and women treated with efavirenz during pregnancy. It is not known whether efavirenz caused these defects. Tell your doctor right away if you are pregnant. Also talk with your doctor if you want to become pregnant.
• Women should not rely only on hormone-based birth control, such as pills, injections, or implants, because efavirenz may make these contraceptives ineffective. Women must use a reliable form of barrier contraception, such as a condom or diaphragm, even if they also use other methods of birth control. Efavirenz may remain in your blood for a time after therapy is stopped. Therefore, you should continue to use contraceptive measures for 12 weeks after you stop taking efavirenz.
• Do not breast-feed if you are taking efavirenz. The Centers for Disease Control and Prevention recommend that mothers with HIV not breastfeed because they can pass the HIV through their milk to the baby. Also, efavirenz may pass through breast milk and cause serious harm to the baby. Talk with your doctor if you are breast-feeding. You may need to stop breastfeeding or use a different medicine.
• Taking efavirenz with alcohol or other medicines causing similar side effects as efavirenz, such as drowsiness, may increase those side effects.
• QTc prolongation. Your doctor will monitor your risk and mya need to changes to other medications you are taking that may increase your risk for QTc prolongation. 
• Rash may be a serious problem in some children. Tell your child’s doctor right away if you notice rash or any other side effects while your child is taking efavirenz.
• Do not take any other medicines without checking with your doctor. These medicines include prescription and nonprescription medicines and herbal products, especially St. John’s wort (Hypericum perforatum).

Grapefruit and grapefruit juice may interact with efavirenz and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Before using efavirenz, tell your doctor if you:

• have problems with your liver or have hepatitis. Your doctor may want to do tests to check your liver while you take efavirenz or may switch you to another medicine.
• have ever had mental illness or are using drugs or alcohol.
• have ever had seizures or are taking medicine for seizures [for example, Dilantin (phenytoin), Tegretol (carbamazepine), or phenobarbital]. Your doctor may want to switch you to another medicine or check drug levels in your blood from time to time.
• are pregnant or breastfeeding.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Women should not become pregnant while taking efavirenz and for 12 weeks after stopping it. Serious birth defects have been seen in the offspring of animals and women treated with efavirenz during pregnancy. It is not known whether efavirenz caused these defects. Tell your doctor right away if you are pregnant. Also talk with your doctor if you want to become pregnant. See "Drug Precautions".

Do not breastfeed if you are taking efavirenz. The Centers for Disease Control and Prevention recommend that mothers with HIV not breastfeed because they can pass the HIV through their milk to the baby. Also, efavirenz may pass through breast milk and cause serious harm to the baby. Talk with your doctor if you are breastfeeding. You may need to stop breastfeeding or use a different medicine.

• You should take efavirenz on an empty stomach, preferably at bedtime.
• Swallow efavirenz with water.
• Taking efavirenz with food increases the amount of medicine in your body, which may increase the frequency of side effects.
• Taking efavirenz at bedtime may make some side effects less bothersome.
• Efavirenz must be taken in combination with other anti-HIV medicines. If you take only efavirenz, the medicine may stop working.
• Do not miss a dose of efavirenz. If you forget to take efavirenz, take the missed dose right away, unless it is almost time for your next dose. Do not double the next dose. Carry on with your regular dosing schedule. If you need help in planning the best times to take your medicine, ask your doctor or pharmacist.
• Take the exact amount of efavirenz your doctor prescribes. Never change the dose on your own. Do not stop this medicine unless your doctor tells you to stop.
• If you believe you took more than the prescribed amount of efavirenz, contact your local Poison Control Center or emergency room right away.
• Tell your doctor if you start any new medicine or change how you take old ones. Your doses may need adjustment.
• When your efavirenz supply starts to run low, get more from your doctor or pharmacy. This is very important because the amount of virus in your blood may increase if the medicine is stopped for even a short time. The virus may develop resistance to efavirenz and become harder to treat.
• Your doctor may want to do blood tests to check for certain side effects while you take efavirenz.

For pediatric patients who cannot swallow capsules, the capsule contents can be administered with a small amount of food or infant formula (1 to 2 teaspoons) using the capsule sprinkle method of administration. The dose of efavirenz for children may be lower than the dose for adults. Your child’s doctor will determine the right dose based on your child’s weight.

Capsule sprinkle method of administration:

Open the capsule carefully to avoid spillage or dispersion of the capsule contents into the air. Hold the capsule horizontally over a small container and carefully twisted to open. 

• Use of infant formula for mixing should only be considered for those young infants who cannot reliably consume solid foods.
  • For young infants receiving the capsule sprinkle-infant formula mixture, the entire capsule contents should be gently mixed into 2 teaspoons of reconstituted room temperature infant formula in a small container by carefully stirring with a small spoon, and then drawing up the mixture into a 10 mL oral dosing syringe for administration.
• For patients able to tolerate solid foods, mix the entire capsule contents with an age-appropriate soft food, such as applesauce, grape jelly, or yogurt, in the small container.

 After administration of the efavirenz-food or -formula mixture, an additional small amount (approximately 2 teaspoons) of food or formula must be added to the empty mixing container, stirred to disperse any remaining efavirenz.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your weight
• your height
• your age
• your gender

Efavirenz should be taken orally once daily on an empty stomach, preferably at bedtime. The recommended adult dose is 600 mg (three 200-mg capsules, taken together or one tablet) once a day. 

The dose of efavirenz for children will be based on weight. 

If you take too much efavirenz call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If efavirenz is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

Efavirenz does not cure HIV or AIDS. People taking efavirenz may still develop other infections and complications. Therefore, it is very important that you stay under the care of your doctor.

Efavirenz has not been shown to reduce the risk of passing HIV to others. Therefore, continue to practice safe sex, and do not use or share dirty needles.

• Keep efavirenz at room temperature (77° F) in the bottle given to you by your pharmacist. The temperature can range from 59° to 86° F.
• Keep efavirenz out of the reach of children.