Efavirenz (patient information)

# Why this medication is prescribed
Efavirenz is used with other medications to treat human immunodeficiency virus (HIV) infection in patients with or without acquired immunodeficiency syndrome (AIDS). Efavirenz is in a class of medications called nonnucleoside reverse transcriptase inhibitors (NNRTIs). Efavirenz works by slowing the spread of HIV in the body. Efavirenz does not cure HIV infection and may not prevent you from developing HIV-related illnesses. Efavirenz does not prevent you from spreading HIV to other people.

# How this medication should be used
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. Take efavirenz at around the same time every day. Taking efavirenz at bedtime may make 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.
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.

# Other uses for this medicine
Efavirenz is also used with another medication to help prevent infection in health care 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.

# Special precautions
Before taking efavirenz:
- tell your doctor and pharmacist if you are allergic to efavirenz or any other medications.
- do not take astemizole (Hismanal) (no longer available in the United States); cisapride (Propulsid) (no longer available in the United States); ergot-type medications such as bromocriptine (Parlodel), cabergoline (Dostinex), dihydroergotamine (D.H.E. 45, Migranal), ergoloid mesylates (Germinal, Hydergine), ergonovine (Ergotrate), ergotamine (Bellergal-S, Cafergot, Ergomar, Wigraine), methylergonovine (Methergine), methysergide (Sansert), and pergolide (Permax); midazolam (Versed); triazolam (Halcion); or voriconazole (Vfend) while taking efavirenz.
- 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: acetaminophen (Tylenol, others); anticoagulants ('blood thinners') such as warfarin (Coumadin); antidepressants; antifungals such as itraconazole (Sporanox), and ketoconazole (Nizoral); calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, Tiazac, others), felodipine (Lexxel, Plendil), nifedipine (Adalat, Procardia), nisoldipine (Sular), and verapamil (Calan, Covera, Isoptin, Verelan); chlorpheniramine in over-the-counter cold products; cholesterol-lowering medications (statins); cimetidine (Tagamet); clarithromycin (Biaxin, Prevpac); danazol (Danocrine); dexamethasone (Decadron); erythromycin (E.E.S., E-Mycin, Erythrocin); iron products; isoniazid (INH, Nydrazid); medications for anxiety, mental illness, or pain; medications for HIV or AIDS such as amprenavir (Agenerase), atazanavir (Reyataz); indinavir (Crixivan), lopinavir (in Kaletra); ritonavir (Norvir, in Kaletra) and saquinavir ( Invirase); medications for seizures such as carbamazepine (Tegretol), phenobarbital, and phenytoin (Dilantin, Phenytek); methotrexate (Rheumatrex); methadone (Dolophine); metronidazole (Flagyl); niacin (nicotinic acid); nonsteroidal anti-inflammatory medications (NSAIDs) such as celecoxib (Celebrex), diclofenac (Voltaren), ibuprofen (Advil, Motrin), naproxen (Aleve, Anaprox, Naprosyn), and piroxicam (Feldene); oral medications for diabetes such as glipizide (Glucotrol, Metaglip) and tolbutamide (Orinase); proton pump inhibitors such as lansoprazole (Prevacid), omeprazole (Prilosec), and pantoprazole (Protonix); quinidine (Quinidex); quinine; rifabutin (Mycobutin); rifampin (Rifadin, Rimactane); sedatives; sertraline (Zoloft); sildenafil (Viagra); sleeping pills; sulfamethoxazole (Bactrim, Septra); tamoxifen (Nolvadex); torsemide (Demadex); tranquilizers; troleandomycin (TAO); or zafirlukast (Accolate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor what herbal products you are taking, especially products that contain kava or St. John's wort.
- tell your doctor if you drink or have ever drunk large amounts of alcohol; if you use or have ever used street drugs or have overused prescription medications; or if you have or have ever had seizures; high cholesterol; depression or other mental illness; or heart, liver,or pancreas disease.
- you should not become pregnant while taking efavirenz. 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 interfere with the action 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. Efavirenz may harm the fetus.
- you should not breastfeed if you are infected with HIV or are taking efavirenz.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you 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 your body fat may increase or move to different areas of your body such as your breasts and upper back.
- 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), or loss of touch with reality. 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.

# Special dietary instructions
Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

# What to do if you forget a dose
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.

# Side effects

## Minor side effects
Efavirenz may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- upset stomach
- vomiting
- stomach pain
- diarrhea
- indigestion
- drowsiness
- dizziness
- headache
- difficulty concentrating
- confusion
- forgetfulness
- nervousness
- strange thoughts
- abnormally happy mood
- difficulty falling asleep or staying asleep
- unusual dreams
- pain

## Severe side effects
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:
- sore throat, cough, fever, chills, or other signs of infection
- rash
- itching
- blisters or sores on skin
- peeling skin
- fainting
- 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  or by phone .

# Storage conditions needed for this medication
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). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

# In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local 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
- strange thoughts

# Other information
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.

# Brand names
- Sustiva

# Brand names of combination products
- Atripla  containing Efavirenz, Emtricitabine, and Tenofovir