Generic Name: Efavirenz Brand Name(s): Efavirenz.

Uses

What is Efavirenz used for?

Efavirenz is commonly used with other HIV medications to help control HIV infection. It helps to decrease the amount of HIV in your body so your immune system can work better. This lowers your chance of getting HIV complications (such as new infections, cancer) and improves your quality of life. Efavirenz belongs to a class of drugs known as non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Efavirenz is not a cure for HIV infection. To decrease your risk of spreading HIV disease to others, do all of the following: (1) continue to take all HIV medications exactly as prescribed by your doctor, (2) always use an effective barrier method (latex or polyurethane condoms/dental dams) during all sexual activity, and (3) do not share personal items (such as needles/syringes, toothbrushes, and razors) that may have contacted blood or other body fluids.

How should I take Efavirenz?

Take this medication by mouth on an empty stomach, without food, usually once daily at bedtime or as directed by your doctor. Taking efavirenz with food increases the blood level of this medication, which may increase your risk of certain side effects.

Swallow this medication whole with water. If you have difficulty swallowing the capsule, it may be opened and the contents mixed gently in a small amount (1 to 2 teaspoons) of soft food such as applesauce, grape jelly, or yogurt. After taking the mixed medication, add 2 more teaspoons of food to the empty mixing container. Swallow the remaining mixture to make sure that you get the entire dose. Swallow within 30 minutes of mixing. Do not eat any food for 2 hours after taking this medication. For babies who cannot eat solid foods, the contents may be mixed in 2 teaspoons of infant formula and drawn up into an oral syringe to be given to the baby.

The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). In children, the dosage is also based on weight.

It is very important to continue taking this medication (and other HIV medications) exactly as prescribed by your doctor. Do not skip any doses. Do not increase your dose, take this drug more often than prescribed, or stop taking it (or other HIV medicines) even for a short time unless directed to do so by your doctor. Skipping or changing your dose without approval from your doctor may cause the amount of virus to increase, make the infection more difficult to treat (resistant), or worsen side effects.

This medication works best when the amount of drug in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same time each day.

How do I store Efavirenz?

Efavirenz is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Efavirenz in the bathroom or the freezer. There may be different brands of Efavirenz that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Efavirenz down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Efavirenz?

Before taking efavirenz, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: mental/mood conditions (such as depression, thoughts of suicide, psychosis), liver problems (such as hepatitis B or C, cirrhosis), drug/substance/alcohol abuse, seizures, high cholesterol/triglyceride levels.

Efavirenz may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using efavirenz, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics “water pills”) or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using efavirenz safely.

This drug may make you dizzy or drowsy or cause trouble concentrating. Alcohol or marijuana can worsen these effects. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana.

A rash may be more common and serious in children taking efavirenz. Report any rash right away. The doctor may prescribe an antihistamine for your child to take before efavirenz is started. Consult the doctor for more information.

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

During pregnancy, this medication should be used only when clearly needed. Treatment can lower the risk of passing HIV infection to your baby, and efavirenz may be part of that treatment. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Because breast milk can transmit HIV, do not breast-feed.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Efavirenz during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this Efavirenz. This Efavirenz is pregnancy risk category D according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Efavirenz?

Dizziness, trouble sleeping, drowsiness, unusual dreams, and trouble concentrating may frequently occur. Theseside effects may begin 1-2 days after starting this medication and usually go away in 2-4 weeks. They are also reduced by taking efavirenz on an empty stomach at bedtime. Avoid alcohol and street drugs while taking efavirenz. They may worsen these side effects.

Tiredness, headache, nausea, vomiting, and diarrhea may also occur.

If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

As your immune system gets stronger, it can begin to fight off infections you already had, possibly causing disease symptoms to come back. You could also have symptoms if your immune system becomes overactive. This reaction may happen at any time (soon after starting HIV treatment or many months later). Get medical help right away if you have any serious symptoms, including: unexplained weight loss, severe tiredness, muscle aches/weakness that doesn’t go away, headaches that are severe or don’t go away, joint pain, numbness/tingling of the hands/feet/arms/legs, vision changes, signs of infection (such as fever, chills, swollen lymph nodes, trouble breathing, cough, non-healing skin sores), signs of an overactive thyroid (such as irritability, nervousness, heat intolerance, fast/pounding/irregular heartbeat, bulging eyes, unusual growth in the neck/thyroid known as a goiter), signs of a certain nerve problem known as Guillain-Barre syndrome (such as trouble breathing/swallowing/moving your eyes, drooping face, paralysis, trouble speaking).

Infrequently, serious psychiatric symptoms may occur during efavirenz treatment, although it is unclear if they are caused by efavirenz. These effects may be seen especially in people who have mental/mood conditions. Tell your doctor right away if any of these unlikely but serious side effects occur: mental/mood changes (such as depression, rare thoughts of suicide, nervousness, angry behavior, hallucinations).

Tell your doctor right away if any of these rare but serioussigns of liver problems (such as persistent nausea/vomiting, stomach/abdominal pain, severe tiredness, yellowing eyes/skin, dark urine).

Changes in body fat may occur while you are taking this medication (such as increased fat in the upper back and stomach areas, decreased fat in the arms and legs). The cause and long-term effects of these changes are unknown. Discuss the risks and benefits of treatment with your doctor, as well as the possible use of exercise to reduce this side effect.

Get medical help right away if you have any very serious side effects, including: fast/irregular heartbeat, severe dizziness, fainting.

Efavirenz can commonly cause a rash that is usually not serious. In adults, a rash may occur in the first 2 weeks after starting treatment and if it is not serious, it will usually resolve in 4 weeks. In children, a rash may occur in the first 4 weeks after starting treatment. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Therefore, seek immediate medical attention if you develop any rash.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, blisters, peeling skin, fever, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Efavirenz?

Some products that may interact with this drug include: a certain combination product used to treat chronic hepatitis C (ombitasvir/paritaprevir/ritonavir/dasabuvir), orlistat.

Do not take this medication with other products that contain efavirenz unless specifically directed by your doctor.

Other medications can affect the removal of efavirenz from your body, which may affect how efavirenz works. Examples include some drugs used to treat seizures (such as carbamazepine, phenobarbital, phenytoin), rifamycins (such as rifampin), among others.

Efavirenz can speed up the removal of many other medications from your body, which may affect how they work. Examples of affected drugs include atovaquone/proguanil, azole antifungals (such as itraconazole, ketoconazole), bedaquiline, cobicistat, macrolide antibiotics (such as clarithromycin), methadone, rifabutin, sertraline, some cholesterol-lowering statins (such as atorvastatin, pravastatin, simvastatin), certain protease inhibitors (boceprevir, simeprevir), warfarin, among others.

Some other drugs to treat HIV infection (such as elvitegravir, other NNRTIs including etravirine/nevirapine/rilpivirine) may also interact with efavirenz. If you are taking atazanavir with this medication, you may need to also take another medication (ritonavir). Consult your doctor or pharmacist for more details.

This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Talk to your doctor about additional or alternative reliable forms of birth control, and always use an effective barrier method (latex or polyurethane condoms/dental dams) during all sexual activity to decrease the risk of spreading HIV to others. Tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your hormonal birth control is not working well. (See also Precautions section.)

Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana, antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

This medication may interfere with certain laboratory tests (including urine cannabinoid tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

Efavirenz may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Efavirenz?

Efavirenz may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Efavirenz?

Efavirenz may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Efavirenz.

What is the dose of Efavirenz for an adult?

Usual Adult Dose for HIV Infection

600 mg orally once a day

Comments:

-This drug should be used with a protease inhibitor and/or NRTIs.

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Usual Adult Dose for Nonoccupational Exposure

US CDC recommendations: 600 mg orally once a day

Duration of therapy: 28 days

Comments:

-This drug should be used with (lamivudine or emtricitabine) plus (zidovudine or tenofovir); recommended as the preferred NNRTI-based regimen for nonoccupational postexposure prophylaxis of HIV infection.

-Prophylaxis should be started as soon as possible, within 72 hours of exposure.

-Not approved by US FDA.

Usual Adult Dose for Occupational Exposure

US Public Health Service working group recommendations: 600 mg orally once a day

Duration of therapy: 28 days, if tolerated

Comments:

-An alternative antiretroviral agent for use as HIV postexposure prophylaxis only with expert consultation

-Prophylaxis should be started as soon as possible, preferably within hours after exposure.

-The optimal duration of prophylaxis is unknown and may differ based on institution protocol.

-The most current therapeutic guidelines should be consulted for more information.

-Not approved by US FDA.

Renal Dose Adjustments

No adjustment recommended.

Liver Dose Adjustments

Mild liver dysfunction: No adjustment recommended; caution recommended.

Moderate to severe liver dysfunction: Not recommended.

Dose Adjustments

Adults:

-If used with voriconazole: Decrease efavirenz dose to 300 mg orally once a day using the capsule formulation; the manufacturer product information should be consulted.

-If used with rifampin in patients weighing 50 kg or more: Increase efavirenz dose to 800 mg orally once a day.

Dialysis

Data not available

Comments: This drug is highly protein-bound; significant removal via dialysis is not likely.

Other Comments

Administration advice:

-Administer on an empty stomach (bedtime preferable); administration with food increases drug levels and may increase rate of side effects.

-Administer at bedtime to improve tolerability of CNS side effects.

-Do not crush tablets; swallow tablets intact with liquid.

-Capsules can be swallowed intact with liquid or administered using the sprinkle method.

-For patients unable to swallow capsules or tablets, the capsule contents can be administered with a small amount (1 to 2 teaspoons) of food; consult the manufacturer product information regarding administration using the sprinkle method.

-Consult the manufacturer product information regarding missed doses.

Reconstitution/preparation techniques:

-The manufacturer product information should be consulted regarding preparation for the capsule sprinkle method of administration.

General:

-This drug should always be used in combination with other antiretroviral agents; it should not be used as a single agent to treat HIV-1.

-This drug should not be added on as a sole agent to a failing regimen.

Monitoring:

-General: Pregnancy testing (before starting this drug)

-Hepatic: Liver enzymes (before and during therapy)

-Metabolic: Triglycerides and cholesterol (before and periodically during therapy)

Patient advice:

-This drug may impair mental abilities needed to perform potentially hazardous tasks (e.g., driving, operating machinery); CNS effects may be additive if used with alcohol or psychoactive drugs. Avoid hazardous tasks if CNS symptoms (e.g., dizziness, impaired concentration, drowsiness) occur.

What is the dose of Efavirenz for a child?

Usual Pediatric Dose for HIV Infection

3 months or older:

3.5 to less than 5 kg: 100 mg orally once a day

5 to less than 7.5 kg: 150 mg orally once a day

7.5 to less than 15 kg: 200 mg orally once a day

15 to less than 20 kg: 250 mg orally once a day

20 to less than 25 kg: 300 mg orally once a day

25 to less than 32.5 kg: 350 mg orally once a day

32.5 to less than 40 kg: 400 mg orally once a day

40 kg or more: 600 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Precautions

Safety and efficacy have not been established in patients younger than 3 months or less than 3.5 kg; this drug is not recommended for use in these patients.

How is Efavirenz available?

Efavirenz is available in the following dosage forms and strengths:

  • Tablet

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Efavirenz, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: January 24, 2018 | Last Modified: January 24, 2018