Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Sustiva


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

This medicine will not cure HIV infection or AIDS. It works by lowering the amount of HIV in the blood and helps the immune system. This may help delay some of the medical conditions that usually result from AIDS or HIV disease. It will not keep you from spreading HIV to other people.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Tablet

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of efavirenz in children younger than 3 months of age or weighing less than 3.5 kilograms (kg). Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of efavirenz in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving efavirenz.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Bepridil
  • Carbamazepine
  • Cisapride
  • Dasabuvir
  • Dronedarone
  • Elbasvir
  • Grazoprevir
  • Levoketoconazole
  • Maraviroc
  • Mavacamten
  • Mesoridazine
  • Paritaprevir
  • Pimozide
  • Piperaquine
  • Ritonavir
  • Saquinavir
  • Sparfloxacin
  • St John's Wort
  • Terfenadine
  • Thioridazine
  • Voriconazole
  • Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Abametapir
  • Adagrasib
  • Alfentanil
  • Alfuzosin
  • Amiodarone
  • Amisulpride
  • Amitriptyline
  • Amprenavir
  • Anagrelide
  • Apomorphine
  • Aripiprazole
  • Aripiprazole Lauroxil
  • Arsenic Trioxide
  • Artemether
  • Asenapine
  • Astemizole
  • Atazanavir
  • Atogepant
  • Atovaquone
  • Avacopan
  • Avanafil
  • Avapritinib
  • Axitinib
  • Azithromycin
  • Bedaquiline
  • Benzhydrocodone
  • Bexarotene
  • Boceprevir
  • Brigatinib
  • Buprenorphine
  • Bupropion
  • Buserelin
  • Cabotegravir
  • Capivasertib
  • Capmatinib
  • Ceritinib
  • Chloroquine
  • Chlorpromazine
  • Ciprofloxacin
  • Citalopram
  • Clarithromycin
  • Clofazimine
  • Clomipramine
  • Clothiapine
  • Clozapine
  • Cobicistat
  • Cobimetinib
  • Codeine
  • Crizotinib
  • Cyclobenzaprine
  • Cyclosporine
  • Dabrafenib
  • Daclatasvir
  • Daridorexant
  • Darunavir
  • Dasatinib
  • Deflazacort
  • Degarelix
  • Delamanid
  • Desipramine
  • Deslorelin
  • Deutetrabenazine
  • Dexamethasone
  • Dexmedetomidine
  • Dienogest
  • Dihydrocodeine
  • Disopyramide
  • Dofetilide
  • Dolasetron
  • Dolutegravir
  • Domperidone
  • Donepezil
  • Doravirine
  • Doxepin
  • Doxorubicin
  • Doxorubicin Hydrochloride Liposome
  • Droperidol
  • Duvelisib
  • Ebastine
  • Elacestrant
  • Encorafenib
  • Entrectinib
  • Enzalutamide
  • Erdafitinib
  • Eribulin
  • Erythromycin
  • Escitalopram
  • Estetrol
  • Estradiol
  • Ethinyl Estradiol
  • Ethynodiol
  • Etrasimod
  • Etravirine
  • Famotidine
  • Fedratinib
  • Felbamate
  • Fentanyl
  • Fexinidazole
  • Finerenone
  • Fingolimod
  • Flecainide
  • Fluconazole
  • Fluoxetine
  • Formoterol
  • Fosamprenavir
  • Foscarnet
  • Fosnetupitant
  • Fosphenytoin
  • Fostemsavir
  • Fruquintinib
  • Galantamine
  • Gatifloxacin
  • Gemifloxacin
  • Gepirone
  • Gestodene
  • Ginkgo Biloba
  • Glasdegib
  • Glecaprevir
  • Gonadorelin
  • Goserelin
  • Granisetron
  • Halofantrine
  • Haloperidol
  • Hemin
  • Histrelin
  • Horsetail
  • Hydrocodone
  • Hydroquinidine
  • Hydroxychloroquine
  • Hydroxyzine
  • Ibrexafungerp
  • Ibutilide
  • Idelalisib
  • Ifosfamide
  • Iloperidone
  • Imipramine
  • Infigratinib
  • Inotuzumab Ozogamicin
  • Itraconazole
  • Ivabradine
  • Ivosidenib
  • Ketoconazole
  • Lapatinib
  • Larotrectinib
  • Lefamulin
  • Lemborexant
  • Lenacapavir
  • Leniolisib
  • Lenvatinib
  • Leuprolide
  • Levofloxacin
  • Levonorgestrel
  • Linagliptin
  • Lofexidine
  • Lorlatinib
  • Lumateperone
  • Lumefantrine
  • Lurasidone
  • Macimorelin
  • Medroxyprogesterone
  • Mefloquine
  • Meperidine
  • Mestranol
  • Methotrexate
  • Methotrimeprazine
  • Metronidazole
  • Mifepristone
  • Mirtazapine
  • Mitapivat
  • Mizolastine
  • Mobocertinib
  • Moricizine
  • Moxifloxacin
  • Nafarelin
  • Nelfinavir
  • Neratinib
  • Netupitant
  • Nevirapine
  • Nifedipine
  • Nilotinib
  • Nirmatrelvir
  • Nirogacestat
  • Nomegestrol
  • Norfloxacin
  • Octreotide
  • Ofloxacin
  • Olanzapine
  • Olaparib
  • Olutasidenib
  • Omaveloxolone
  • Ondansetron
  • Orlistat
  • Osilodrostat
  • Osimertinib
  • Oxaliplatin
  • Oxycodone
  • Ozanimod
  • Pacritinib
  • Paliperidone
  • Palovarotene
  • Panobinostat
  • Papaverine
  • Paroxetine
  • Pasireotide
  • Pazopanib
  • Pemigatinib
  • Pentamidine
  • Pentazocine
  • Perampanel
  • Perphenazine
  • Phenobarbital
  • Pibrentasvir
  • Pimavanserin
  • Pipamperone
  • Pirtobrutinib
  • Pitolisant
  • Ponesimod
  • Posaconazole
  • Pralsetinib
  • Praziquantel
  • Pretomanid
  • Primidone
  • Probucol
  • Procainamide
  • Prochlorperazine
  • Proguanil
  • Promethazine
  • Propafenone
  • Protriptyline
  • Quetiapine
  • Quinidine
  • Quinine
  • Quizartinib
  • Ranolazine
  • Relugolix
  • Repotrectinib
  • Ribociclib
  • Rifabutin
  • Rifampin
  • Rilpivirine
  • Rimegepant
  • Ripretinib
  • Risperidone
  • Segesterone
  • Selpercatinib
  • Selumetinib
  • Sertindole
  • Sertraline
  • Sevoflurane
  • Sildenafil
  • Simeprevir
  • Siponimod
  • Sirolimus
  • Sodium Phosphate
  • Sodium Phosphate, Dibasic
  • Sodium Phosphate, Monobasic
  • Solifenacin
  • Sonidegib
  • Sorafenib
  • Sotalol
  • Sparsentan
  • Sufentanil
  • Sulpiride
  • Sultopride
  • Sunitinib
  • Tacrolimus
  • Tamoxifen
  • Tazemetostat
  • Telavancin
  • Telithromycin
  • Tetrabenazine
  • Tolterodine
  • Tolvaptan
  • Toremifene
  • Tramadol
  • Trazodone
  • Triclabendazole
  • Trimipramine
  • Triptorelin
  • Ubrogepant
  • Ulipristal
  • Valoctocogene Roxaparvovec-rvox
  • Vandetanib
  • Vardenafil
  • Velpatasvir
  • Vemurafenib
  • Venetoclax
  • Venlafaxine
  • Vilanterol
  • Vinflunine
  • Voclosporin
  • Vonoprazan
  • Vorinostat
  • Voxelotor
  • Voxilaprevir
  • Warfarin
  • Zanubrutinib
  • Zolpidem
  • Zotepine
  • Zuclopenthixol
  • Zuranolone

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Atorvastatin
  • Caspofungin
  • Diltiazem
  • Etonogestrel
  • Indinavir
  • Lopinavir
  • Norgestimate
  • Ospemifene
  • Pravastatin
  • Simvastatin
  • Telaprevir

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Alcohol or drug abuse, history of or
  • Depression, history of or
  • Mental illness, history of—May increase the chance of having serious psychiatric side effects.
  • Hepatitis B or
  • Hepatitis C or
  • Liver disease, mild or
  • QT prolongation (heart rhythm problem) or
  • Seizures, history of—Use with caution. May make these conditions worse.
  • Liver disease, moderate or severe—Use is not recommended in patients with this condition.

Proper Use

Take this medicine exactly as directed by your doctor. Do not take it more often, and do not take it for a longer time than your doctor ordered.

Do not change the dose or stop using this medicine without checking first with your doctor. When your supply of this medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of this medicine.

This medicine comes with a patient information leaflet and patient instructions. Read and follow the instructions carefully. Ask your doctor if you have any questions. Read it again each time you refill your prescription in case there is new information. You should talk to your doctor if you have any questions.

Keep taking efavirenz for the full time of treatment, even if you begin to feel better. It is also important that you continue taking all other medicines for HIV infection your doctor has instructed you to take. Efavirenz will not work if it is taken alone. It must be taken with other HIV medicines.

This medicine works best when there is a constant amount in the blood. To help keep blood levels constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times during the day. For example, if you or your child are taking one dose per day, try to take it at the same time each day. If you need help planning the best times to take your medicine, check with your doctor.

Take this medicine on an empty stomach at bedtime.

Swallow the capsule or tablet whole with water. Do not break, crush, or chew the tablet.

If you or your child are unable to swallow the capsule whole:

  • Wash and dry your hands well.
  • Gather a teaspoon, a spoon for stirring, and a small clean container such as a small cup or bowl.
  • Open the capsule and pour the contents into 1 to 2 teaspoons of soft food (including applesauce, grape jelly, or yogurt) in the container. You may instead mix the medicine into infant formula in the container.
  • Using the small spoon, gently mix the capsule contents and food together. It will not completely dissolve. Mixture will look grainy but should not be lumpy.
  • The mixture should be taken or given within 30 minutes. Use the small spoon to give or take the mixture. If you use the oral syringe, place the tip into the container. Slowly pull back on the plunger and draw up the mixture.
  • Place the tip of the syringe in your baby's mouth along the inner cheek. Slowly push on the plunger to give your baby all of the mixture.
  • Add another 2 teaspoons of the soft food into the empty container and gently stir with the small spoon to mix any remaining capsule contents. Give or take the mixture with the spoon or syringe as above.
  • Do not eat anything else for 2 hours after taking this medicine mixed with food or formula.

Tell your doctor if you take rifampin (Rifadin®, Rifamate®, Rifater®) or voriconazole (Vfend®). Your dose may need to be changed.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For HIV infection:
    • For oral dosage form (capsules):
      • Adults and children 3 months of age and older or weighing 40 kilograms or more—600 milligrams (mg) once a day.
      • Children 3 months of age and older weighing less than 40 kg—Dose is base on body weight and must be determined by your doctor.
        • Weighing 32.5 kg to less than 40 kg—400 mg (two 200 mg capsules) once a day.
        • Weighing 25 kg to less than 32.5 kg—350 mg (one 200 mg and three 50 mg capsules) once a day.
        • Weighing 20 kg to less than 25 kg—300 mg (one 200 mg and two 50 mg capsules) once a day.
        • Weighing 15 kg to less than 20 kg—250 mg (one 200 mg and one 50 mg capsules) once a day.
        • Weighing 7.5 kg to less than 15 kg—200 mg once a day.
        • Weighing 5 kg to less than 7.5 kg—150 mg (three 50 mg capsules) once a day.
        • Weighing 3.5 kg to less than 5 kg—100 mg (two 50 mg capsules) once a day.
      • Children younger than 3 months of age and weighing less than 3.5 kg—Use is not recommended.
    • For oral dosage form (tablets):
      • Adults and children weighing 40 kilograms (kg) or more—600 milligrams (mg) once a day, taken with other medicines.
      • Children weighing less than 40 kg—Use of capsule is recommended.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.


It is very important that your doctor check the progress of you or your child at regular visits, to make sure this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting this medicine. Use an effective form of birth control to keep from getting pregnant. You should not become pregnant during treatment and for 12 weeks after the last dose. If you think you have become pregnant while using the medicine, tell your doctor right away.

This medicine may decrease the effects of some birth control including pills, injections, or implants. To avoid getting pregnant, use an additional form of birth control along with your pills, injections, or implant and for 12 weeks after stopping it. Other forms of birth control include a condom, a diaphragm, contraceptive foam, or jelly.

Do not use this medicine together with elbasvir/grazoprevir (Zepatier®). Do not take other medicines that contain efavirenz (eg, efavirenz/emtricitabine/tenofovir, Atripla®).

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem including QT prolongation.

You might have mood or behavior changes with this medicine, including feeling sad or hopeless, or getting upset easily. You could feel nervous or hostile, or have decreased awareness or responsiveness. Some people become violent and want to hurt themselves or others. Call your doctor right away if you or your child have any strange feelings, thoughts, or behaviors.

This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Even if taken at bedtime, it may cause some people to feel drowsy or less alert on arising. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Check with your doctor before taking efavirenz with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with efavirenz may worsen the side effects of this medicine, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.

Tell your doctor if you or your child get any type of skin rash, even a mild rash. Call your doctor right away if you or your child have a rash with blisters, a fever, mouth sores, red or irritated eyes, swelling of the face, muscle or joint pain, or muscle weakness.

Liver problems may occur while you are using this medicine. Check with your doctor right away if you or your child has stomach pain or tenderness, clay-colored stools, dark urine, a fever, a headache, itching, loss of appetite, nausea and vomiting, skin rash, swelling of the feet or lower legs, unusual tiredness or weakness, or yellow eyes or skin.

This medicine may increase the level of cholesterol and fats in your blood. If this condition occurs, your doctor may give you a medicine to lower the cholesterol and fats. Talk to your doctor if you have concerns.

Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you or your child notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia, herpes, or tuberculosis. Autoimmune disorders (eg, Graves' disease, polymyositis, and Guillain-Barré syndrome) may also occur.

Efavirenz may cause you to have excess body fat. Tell your doctor if you or your child notice changes in your body shape, including an increased amount of body fat in your neck or upper back, around your chest, or stomach area. You might also lose fat from your legs, arms, and face.

This medicine does not decrease the risk of transmitting the HIV infection to others through sexual contact or by contaminated blood. Make sure you understand and practice safe sex, even if your partner also has HIV. Avoid sharing needles with anyone.

Tell the doctor in charge that you or your child are taking this medicine before you have any medical tests. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Depression
  2. skin rash or itching

Less common

  1. Blood in the urine
  2. difficult or painful urination
  3. pain in the lower back or side


  1. Blistering
  2. changes in vision
  3. chest tightness
  4. clumsiness or unsteadiness
  5. confusion
  6. convulsions (seizures)
  7. cough
  8. dark urine
  9. delusions
  10. double vision
  11. fainting
  12. fast or pounding heartbeat
  13. fever or chills
  14. headache (severe and throbbing)
  15. hives
  16. inappropriate behavior
  17. loss of appetite
  18. mood or mental changes (severe)
  19. muscle cramps or pain
  20. nausea or vomiting
  21. nerve pain
  22. open sores
  23. pain, tenderness, bluish color, or swelling of the leg or foot
  24. rapid weight gain
  25. seeing, hearing, or feeling things that are not there
  26. sense of constant movement of self or surroundings
  27. sores, ulcers, or white spots in the mouth or on the lips
  28. speech disorder
  29. stomach pain
  30. swelling or tenderness in the upper abdominal or stomach area
  31. swelling of the hands, arms, feet, or legs
  32. thoughts of suicide or attempts at suicide
  33. tingling, burning, numbness, or pain in the hands, arms, feet, or legs
  34. tingling, burning, or prickling sensations
  35. tremor
  36. trouble breathing
  37. unusual tiredness
  38. weight loss
  39. yellow eyes or skin

Incidence not known

  1. Actions that are out of control
  2. attack, assault, or force
  3. continuing vomiting
  4. decreased awareness or responsiveness
  5. delusions of persecution, mistrust, suspiciousness, or combativeness
  6. difficult or labored breathing
  7. early appearance of redness or swelling of the skin
  8. general feeling of tiredness or weakness
  9. irregular heartbeat recurrent
  10. irritability
  11. late appearance of rash with or without weeping blisters that become crusted, especially in sun-exposed areas of the skin, may extend to unexposed areas
  12. light-colored stools
  13. mimicry of speech or movements
  14. mutism
  15. negativism
  16. nervousness
  17. peculiar postures or movements, mannerisms, or grimacing
  18. severe sleepiness
  19. talking, feeling, and acting with excitement

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Diarrhea
  2. dizziness
  3. drowsiness
  4. headache
  5. increased sweating
  6. poor concentration
  7. trouble sleeping

Less common or rare

  1. Abnormally decreased sensitivity, particularly to touch
  2. agitation or anxiety
  3. belching
  4. change in sense of taste or smell
  5. dry mouth
  6. excessive gas
  7. false sense of well-being
  8. flaking and falling off of the skin
  9. flushing
  10. general feeling of discomfort
  11. heartburn
  12. indigestion
  13. joint pain
  14. lack of feeling or emotion
  15. loss of hair
  16. loss of memory
  17. loss of sense of reality
  18. mood changes
  19. pain
  20. painful, red, hot, or irritated hair follicles
  21. ringing in the ears
  22. stomach discomfort
  23. unusual dreams
  24. weakness

Incidence not known

  1. Difficulty having a bowel movement (stool)
  2. discoloration of the fingernails or toenails
  3. dizziness or lightheadedness
  4. feeling of constant movement of self or surroundings
  5. increased amount of fat in the upper back and neck, or around the chest and stomach area
  6. lose fat from the legs, arms, and face
  7. sensation of spinning
  8. swelling of the breasts or breast soreness in both females and males

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.