Efavirenz is used along with other medications to treat human immunodeficiency virus (HIV) infection. Efavirenz is in a class of medications called non-nucleoside reverse transcriptase inhibitors (NNRTIs). It works by decreasing the amount of HIV in the blood. Although efavirenz does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other life-style changes may decrease the risk of transmitting (spreading) the HIV virus to other people.

Efavirenz comes as a capsule and as a tablet to take by mouth. It is usually taken once a day with plenty of water on an empty stomach (at least 1 hour before or 2 hours after a meal). Take efavirenz at around the same time every day. Taking efavirenz at bedtime may make certain side effects less bothersome. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take efavirenz exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets and capsules whole; do not split, chew, or crush them.

If you are not able to swallow the medication whole, you can still take efavirenz by mixing the contents of the capsule with soft food and eating. To prepare each dose, open the capsule and sprinkle the contents onto 1-2 teaspoons of soft food in a small container. You can use soft foods such as applesauce, grape jelly, or yogurt. While sprinkling, be careful not to spill the contents of the capsule, or spread it in the air. Mix the medicine with the soft food. The mixture should look grainy but should not be lumpy. You must eat the medicine and soft food mixture within 30 minutes of mixing. When you are finished, add another 2 teaspoons of soft food to the empty container, stir, and eat to be sure that you have received the full dose of medication. Do not eat for the next 2 hours.

If efavirenz is being given to a baby who can not yet eat solid foods, the contents of the capsule can be mixed with 2 teaspoons of room temperature infant formula in a small container. While emptying the capsule, be careful not to spill the contents, or spread it in the air. The mixture should look grainy but should not be lumpy. The mixture should be syringe fed to the baby within 30 minutes of mixing. When finished, add an additional 2 teaspoons of infant formula to the empty container, stir, and syringe feed to the baby to be sure that you have given the full dose of medication. Do not give the medication to the baby in a bottle. Do not feed the baby for the next 2 hours.

Efavirenz controls HIV infection, but does not cure it. Continue to take efavirenz even if you feel well. Do not stop taking efavirenz without talking to your doctor. When your supply of efavirenz starts to run low, get more from your doctor or pharmacist. If you miss doses or stop taking efavirenz, your condition may become more difficult to treat.

Efavirenz is also used with other medications to help prevent infection in healthcare workers or other people who were accidentally exposed to HIV. Talk to your doctor about the possible risks of using this medication for your condition.

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

Before taking efavirenz,

• Tell your doctor and pharmacist if you are allergic to efavirenz any other medications, or if you are allergic to any of the ingredients in efavirenz capsules or tablets. Ask your doctor or pharmacist for a list of the ingredients.
• You should know that efavirenz is also available in combination with another medication with the brand name of Atripla. Tell your doctor if you are taking this medication to be sure you do not receive the same medication twice.
• Tell your doctor if you are taking elbasvir and grazoprevir (Zepatier). Your doctor will probably tell you not to take efavirenz if you are taking this medication.
• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: antidepressants, artemether and lumefantrine (Coartem), atazanavir (Reyataz), atorvastatin (Lipitor, in Caduet), atovaquone and proguanil, bupropion (Wellbutrin, Zyban, others, in Contrave), carbamazepine (Carbatrol, Epitol, Equetro, Tegretol, Teril), clarithromycin (Biaxin, in Prevpac), cyclosporine (Gengraf, Neoral, Sandimmune), delavirdine (Rescriptor), diltiazem (Cardizem CD, Cartia XT, Diltzac, Taztia XT), ethinyl estradiol and norgestimate (Estarylla, Ortho-Tri-Cyclen, Sprintec, others), etravirine (Intelence), etonogestrel (Implanon, Nexplanon, Nuvaring), felodipine, fosamprenavir (Lexiva), itraconazole (Sporanox), indinavir (Crixivan), levonorgestrel (Mirena, Plan B one step, Skyla, in Climera Pro, Seasonale, others), lopinavir (in Kaletra), maraviroc (Selzentry), medications for anxiety, medications for mental illness, medications for seizures, methadone (Dolophine, Methadose), nevirapine (Viramune), nicardipine (Cardene), nifedipine (Adalat, Afeditab, Procardia XL), norelgestromin (in Xulane), phenobarbital, phenytoin (Dilantin, Phenytek), posaconazole (Noxafil), pravastatin (Pravachol), rifabutin (Mycobutin), rifampin (Rifadin, Rimactane, in Rifamate, Rifater), rilpivirine (Edurant, in Complera, Odefsey), ritonavir (Norvir, in Kaletra, Technivie, Viekira), saquinavir (Invirase), sedatives, sertraline (Zoloft), simeprevir (Olysio), simvastatin (Zocor, in Vytorin), sirolimus (Rapamune), sleeping pills, tacrolimus (Envarsus XR, Prograf), tranquilizers, verapamil (Calan, Covera, Verelan, in Tarka), voriconazole (Vfend), and warfarin (Coumadin, Jantoven). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with efavirenz, or may increase the risk that you will develop an irregular heartbeat, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• Tell your doctor what herbal products you are taking, especially St. John’s wort.
• Tell your doctor if you have or have ever had prolonged QT interval (a rare heart problem that may cause fainting or irregular heartbeat), irregular heartbeat, other heart problems, have ever drunk large amounts of alcohol, used street drugs, or over-used prescription medications. Also tell your doctor if you have or have ever had depression or other mental illness, seizures, hepatitis (a viral infection of the liver) or any other liver disease disease.
• Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant during your treatment and for 12 weeks after your final dose. If you can become pregnant, you will have to have a negative pregnancy test before you begin taking this medication and use effective birth control during your treatment. Efavirenz may decrease the effectiveness of hormonal contraceptives (birth control pills, patches, rings, implants, or injections), so you should not use these as your only method of birth control during your treatment. You must use a barrier method of birth control (device that blocks sperm from entering the uterus such as a condom or a diaphragm) along with any other method of birth control you have chosen. Ask your doctor to help you choose a method of birth control that will work for you. If you become pregnant while taking efavirenz, call your doctor.
• You should not breast-feed if you are infected with HIV or are taking efavirenz.
• You should know that efavirenz may make you drowsy, dizzy, or unable to concentrate. Do not drive a car or operate machinery until you know how this medication affects you.
• Ask your doctor about the safe use of alcoholic beverages while you are taking efavirenz. Alcohol can make the side effects from efavirenz worse.
• You should know that while you are taking medications to treat HIV infection, your immune system may get stronger and begin to fight other infections that were already in your body or cause other conditions to occur. This may cause you to develop symptoms of those infections or conditions. If you have new or worsening symptoms during your treatment with efavirenz, be sure to tell your doctor.
• You should know that your body fat may increase or move to different areas of your body such as your breasts and upper back, neck (”buffalo hump”), and around your stomach. You may notice a loss of body fat from your face, legs, and arms.
• You should know that efavirenz may cause changes in your thoughts, behavior, or mental health. Call your doctor immediately if you develop any of the following symptoms while you are taking efavirenz: depression, thinking about killing yourself or planning or trying to do so, angry or aggressive behavior, hallucinations (seeing things or hearing voices that do not exist), loss of touch with reality, or other strange thoughts. Be sure your family knows which symptoms may be serious so that they can call your doctor if you are unable to seek treatment on your own.
• You should know that efavirenz may cause potentially serious nervous system problems, including encephalopathy (a serious and potentially fatal disorder of the brain) months or years after you first take efavirenz. Although nervous system problems may begin after you have taken efavirenz for some time, it is important for you and your doctor to realize that they may be caused by efavirenz. Call your doctor right away if you experience problems with balance or coordination, confusion, memory problems, and other difficulties caused by abnormal brain function, at any time during your treatment with efavirenz. Your doctor may tell you to stop taking efavirenz.

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Efavirenz may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• Nausea
• Vomiting
• Stomach pain
• Diarrhea
• Indigestion
• Headache
• Confusion
• Forgetfulness
• Feeling anxious, nervous, or agitated
• Abnormally happy mood
• Difficulty falling asleep or staying asleep
• Unusual dreams
• Pain

Some side effects can be serious. If you experience any of the following symptoms or those mentioned in the SPECIAL PRECAUTIONS section, call your doctor immediately:

• Fever
• Rash
• Itching
• Peeling, blistering, or shedding skin
• Mouth sores
• Pink eye
• Swelling of your face
• Fainting
• Irregular heartbeat
• Extreme tiredness
• Lack of energy
• Loss of appetite
• Pain in the upper right part of the stomach
• Unusual bleeding or bruising
• Yellowing of the skin or eyes
• Flu-like symptoms
• Seizures

Efavirenz may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• Movements of your body that you cannot control
• Dizziness
• Headache
• Difficulty concentrating
• Nervousness
• Confusion
• Forgetfulness
• Difficulty falling asleep or staying asleep
• Unusual dreams
• Drowsiness
• Hallucinations (seeing things or hearing voices that do not exist)
• Abnormally happy mood
• Atrange thoughts

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body’s response to efavirenz.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking efavirenz.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.