Efavirenz | Side Effects, Dosage, Uses & More
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Generic Name:

efavirenz, Oral tablet

All Brands

  • Sustiva
SECTION 1 of 5

Highlights for efavirenz

Oral tablet
1

Efavirenz is always used in combination with other antiretroviral drugs to treat human immunodeficiency virus (HIV).

2

To reduce side effects, it’s best to take it once daily at bedtime on an empty stomach.

3

Two possible troublesome side effects are unusual dreams and depression. Some people have to stop taking the drug due to these side effects.

4

Pregnant women exposed to the drug in their first trimester have had babies with birth defects. Your doctor will make sure you aren’t pregnant before giving you the drug. You will also need to use two forms of birth control while taking it.

5

The dose is usually 600 mg once a day taken at bedtime. The drug is available as an oral tablet or oral capsule. Talk to your doctor about a dose and form that’s right for you.

IMPORTANT INFORMATION

Depression and mood problems

If you experience serious depression after starting the drug, call your doctor right away.

May cause liver problems

Your doctor should run liver function tests before and during treatment with this drug. If you already have liver disease, such as hepatitis B or C, you’re at greater risk.

Atripla combination warning

Don’t combine efavirenz with Atripla unless your doctor prescribes it for you. Atripla is a combination drug that contains efavirenz. Combining the two could increase side effects.

What is efavirenz?

Efavirenz is a prescription drug. It’s available as an oral tablet and an oral capsule. 

Efavirenz is available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.

Efavirenz is always used in combination with other antiretroviral drugs.

Why it's used

Efavirenz is approved to treat HIV infection in adults and children who are at least 3 months old and weigh at least 7.7 pounds (3.5 kg).

How it works

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI).

More Details

How It Works

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI). This class of medication attaches to HIV and blocks an enzyme called reverse transcriptase. The HIV virus uses this enzyme to make copies of itself in your body. Efavirenz isn’t a cure for HIV, but it can slow its progression.

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efavirenz Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with efavirenz include:

  • changes in body fat, such as increased body fat in the back of your neck

  • increased cholesterol and triglyceride levels. Your doctor will monitor your levels. You may need to start cholesterol-lowering drugs while taking efavirenz.

  • rash, usually during the first week or two of treatment. The rash usually disappears within four weeks. If the rash becomes severe or suddenly gets worse, see a doctor right away.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • serious depression or other mood problems, including thinking of suicide

  • liver disease or liver enlargement. Symptoms may include:

    • dark urine
    • loss of appetite
    • fatigue
    • jaundice or yellowing skin
    • nausea
    • tenderness in the stomach area
  • birth defects. Your baby could have birth defects if you take efavirenz in the first trimester. If you’re pregnant or are thinking of becoming pregnant, talk to your doctor before taking efavirenz.

  • convulsions or seizures. Your risk is greater if you have a history of seizures.

  • symptoms of infection, including fungal infection, pneumonia, or tuberculosis. These may indicate immune reconstitution syndrome (IRS). In IRS, your improved immune system may cause infections you’ve had in the past to return. Your doctor may need to treat the old infection if this happens.

Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Efavirenz may cause drowsiness.

According to a study cited in the U.S. Food and Drug Administration’s prescribing information, 50.7% of people who took efavirenz experienced mild to moderate symptoms associated with nervous system impairment. These include:

  • insomnia
  • dizziness
  • difficulty concentrating

Nervous system symptoms are more tolerable if you take the drug at bedtime. Most of these symptoms happen during the first day or two and will disappear after 2–4 weeks.

If you experience more serious symptoms, like hallucinations, depression, or thoughts of suicide, get immediate medical attention.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

efavirenz May Interact with Other Medications

Oral tablet

Efavirenz can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol Interaction

Alcohol and efavirenz are both processed in your liver. Mixing the drug with alcohol can cause extra stress on your liver. This could increase your risk for developing liver disease.

Additionally, drinking alcohol while taking efavirenz can lead to excessive sleepiness.

Medications That Might Interact with This Drug

Human immunodeficiency virus (HIV) drugs
  • atazanavir (Reyataz)
  • fosamprenavir (Lexiva)
  • indinavir (Crixivan)
  • lopinavir/ritonavir (Kaletra)
  • maraviroc (Selzentry)
  • raltegravir (Isentress)
  • ritonavir (Norvir)
  • saquinavir (Invirase)

Antibiotics and other drugs to treat infections
  • artemether and lumefantrine (Coartem) for malaria
  • clarithromycin
  • rifabutin
  • rifampin

Antidepressants
  • bupropion
  • sertraline

Antifungal drugs
  • ketoconazole
  • itraconazole
  • posaconazole
  • voriconazole

Blood thinner, or anticoagulant
  • warfarin

Cholesterol-lowering drugs
  • atorvastatin (Lipitor)
  • pravastatin (Pravachol)
  • simvastatin (Zocor)

Epilepsy drugs
  • carbamazepine
  • phenytoin
  • phenobarbital

Heart drugs, calcium channel blockers
  • diltiazem
  • nifedipine
  • verapamil

Hepatitis drugs
  • boceprevir (Victrelis) for hepatitis C
  • telaprevir (Incivek) for hepatitis C

Oral contraceptives/hormones
  • ethinyl estradiol

Pain Drug
  • methadone

Post-transplant drugs (immunosuppressants)
  • cyclosporine
  • tacrolimus
  • sirolimus (Rapamycin)

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Efavirenz warnings
mental illness
People with depression, mental illness

If you’re currently being treated for depression or other mental illness, talk to your doctor before taking efavirenz. Many people experience depression and other psychiatric side effects while taking the drug. There might be a better drug treatment for you.

liver
People with liver disease

If you have liver disease, such as hepatitis B or C, your doctor may test your liver function more carefully while you take efavirenz. Or, your doctor may not prescribe efavirenz for you. There haven’t been good scientific studies of efavirenz in people with liver disease.

pregnant woman
Pregnant women

Efavirenz is a category D pregnancy drug. That means two things:

  1. Studies show a risk of adverse effects to the fetus when the mother takes the drug.
  2. This drug should only be used during pregnancy in serious cases where it's needed to treat a dangerous condition in the mother.

Taking efavirenz while pregnant increases risk for birth defects. However, you and your doctor may decide that the benefit of taking efavirenz is more important than the risks.

Women should use barrier contraception (condoms, diaphragms, or cervical caps) combined with other methods of birth control (like oral contraceptives) while taking efavirenz.

Women should use barrier and other contraception for 12 weeks after stopping efavirenz.

Be sure to use two forms of birth control and have a negative pregnancy test before starting efavirenz.

breastfeeding
Women who are nursing

The Centers for Disease Control and Prevention recommends that women with HIV do not breastfeed in order to avoid passing HIV through breast milk.

In addition, the drug may be passed through breast milk. If the drug reaches the baby, it can cause possible side effects in the baby.

children
For Children

efavirenz is approved for children at least 3 months old who weigh at least 7.7 pounds (3.5 kg). A child’s dose is based on their body weight. Your pediatrician will decide the correct dose for your child.

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How to Take efavirenz (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What Are You Taking This Medication For?

Human immunodeficiency virus (HIV)

Brand: Sustiva

Form: Oral tablet
Strength: 600 mg
Form: Oral capsule
Strength: 50 mg and 200 mg

Generic: efavirenz

Form: Oral tablet
Strength: 50 mg, 100 mg, 200 mg, and 600 mg
Form: Oral capsule
Strength: 50 mg, 100 mg, and 200 mg
Adult Dosage (ages 18-64 years)

Oral tablet: 600 mg tablet taken once a day.

Child Dosage (ages 3 months-17 years and weighing between 7.7 pounds and 40 pounds)
  • The dose of this medication is based on the child’s body weight. Your doctor will provide the specific dose for your child.
  • In smaller children, the capsule contents can be administered with a small amount of food or infant formula.
  • The dose is given once a day.
Senior Dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A normal adult dose may cause levels of the drug to be higher than normal. If you’re a senior, you may need a lower dose or you may need a different schedule.

Special considerations

Liver Disease: If you have liver disease, such as hepatitis B or C, your doctor may test your liver function more carefully while you take efavirenz. Or, they may not prescribe efavirenz for you. There have not been good scientific studies of efavirenz use in people with liver disease.

Kidney Disease: If you have kidney disease, your kidneys may run less efficiently. Your doctor may watch your kidney function tests more closely than usual. There have been no studies done to see if people with kidney disease need a different dose of efavirenz.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Keeping HIV under control requires long-term treatment and long-term effort. There can be very serious health consequences if you don’t take this drug exactly how your doctor tells you.

If You Stop Taking It or Miss a Dose

If you stop taking this medication or miss doses, your HIV can become worse. You may have many more serious infections and HIV-related problems.

If You Don’t Take It on Schedule

Taking this drug at the same time every day increases your ability to keep the virus under control. If you don’t, you risk worsened infection.

What To Do if I Miss a Dose

In most cases, if you forget to take your dose, take it as soon as you remember. However, if it's just a few hours until your next dose, wait and take a single dose at the usual time.

Take just one dose at a time. Never try to catch up by taking two doses at once. This could result in toxic side effects.

How Can I Tell if the Drug Is Working?

To see how well your treatment is working, your doctor will check your:

  • virus count. The virus count measures the number of copies of the HIV virus in your body.
  • CD4 count. A CD4 count measures the amount of CD4 cells in your body. CD4 cells are white blood cells that fight infection. An increased CD4 count is a sign that your HIV treatment is working.

Efavirenz is a long-term drug.

Take efavirenz on an empty stomach

Taking it with food can increase its absorption, causing more side effects.

Don’t cut or crush the tablet or capsule

Efavirenz tablets are film-coated and shouldn’t be crushed.

The oral capsule can be emptied and mixed with a small amount of food or formula for those who can’t swallow oral tablets. The food or formula mixture should be administered within 30 minutes of mixing and no additional food should be consumed for two hours after administration.

Store efavirenz tablets and capsules at 77°F (25°C)

They may be kept for short periods of time in temperatures as low as 59°F (15°C) and as high as 86°F (30°C).

Avoid exposure to direct sunlight or moisture.

Note: Be careful of moist environments, including bathrooms. To keep drugs away from moisture, store them somewhere other than your bathroom and any other damp location.

Clinical Monitoring

To see how well your treatment is working, your doctor will check your:

  • virus count. The virus count measures the number of copies of the HIV virus in your body.
  • CD4 count. A CD4 count measures the amount of CD4 cells in your body. CD4 cells are white blood cells that fight infection. An increased CD4 count is a sign that your HIV treatment is working.

Liver Function: Your doctor will test your liver function before and during treatment. Some people have had changes in liver enzyme blood tests while taking the drug. If you have hepatitis B (HBV) or hepatitis C (HCV) you’re at higher risk.

Cholesterol, Triglycerides: Efavirenz can cause your cholesterol and triglycerides to go up. Your doctor will check your cholesterol with a blood test.

Not every pharmacy stocks this drug, so call ahead

If you only need a few tablets or capsules, you should call and ask if your pharmacy dispenses only a small number of tablets or capsules. Some pharmacies can't dispense only part of a bottle.

This drug is often available from specialty pharmacies through your insurance plan. These pharmacies operate like mail order pharmacies and ship the drug to you.

In larger cities, there will often be HIV pharmacies where you can have your prescriptions filled. Ask your doctor if there's an HIV pharmacy in your area.

Insurance

Many insurance companies will require a prior authorization before they approve the prescription and pay for efavirenz. Your doctor may need to do paperwork for you, which could take a week or two.

Are There Any Alternatives?

There are other drugs and combinations that can treat HIV. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

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How Much Does efavirenz Cost?

Oral tablet

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These prices represent the lowest priced national pharmacies for efavirenz on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with Susan J. Bliss, RPh, MBA

Medically reviewed by Alan Carter, PharmD and Stacey Boudreaux, PharmD on March 24, 2016

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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