EFAVIRENZ (Systemic)

Some commonly used brand names are:

In the U.S.?

• Sustiva

Category

• Antiviral (systemic)

Description

Efavirenz (eh-FAH-vih-rehnz) is used with other medicines in the treatmentof the infection caused by the human immunodeficiency virus (HIV). HIV isthe virus that causes acquired immune deficiency syndrome (AIDS).

Efavirenz will not cure or prevent HIV infection or AIDS; however, it helpskeep HIV from reproducing and appears to slow down the destruction of theimmune system. This may help delay the development of problems that usuallyresult from AIDS or HIV disease. Efavirenz will not keep you from spreadingHIV to other people. People who receive this medicine may continue to havesome of the problems usually related to AIDS or HIV disease.

This medicine is available only with your doctor's prescription, in thefollowing dosage form(s):

Oral
• Capsules (U.S.)
• Tablets (U.S.)

Before Using This Medicine

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

Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to efavirenz. Also tell your health care professional ifyou are allergic to any other substances, such as foods, preservatives, ordyes.

Pregnancy?Efavirenz has been shown to cause birth defects inhumans. However, this medicine may be needed in serious diseases or othersituations that threaten the mother's life. A pregnancy test is recommendedbefore starting treatment with efavirenz. In addition, it is recommended thatwomen with the potential to become pregnant use two methods of contraception.One method of contraception should be a reliable barrier contraceptive, suchas condoms, and the other method should be an oral or other hormone contraceptive,such as birth control pills. Before taking efavirenz, make sure your doctorknows if you are pregnant or if you may become pregnant.

Breast-feeding?It is not known whether efavirenz passes into thebreast milk. However, patients with HIV infection should not breast-feed becauseof the risk of passing the virus on to the nursing infant.

Children?Children have a higher risk of developing a rash,which is sometimes severe, while taking this medicine. Your doctor may suggestthat an additional medicine, an antihistamine, be taken to prevent a rashfrom occurring. The appearance of a rash should be reported to your doctoras soon as possible.

Older adults?Many medicines have not been studied specificallyin older people. Therefore, it may not be known whether they work exactlythe same way they do in younger adults or if they cause different side effectsor problems in older people. There is no specific information comparing useof efavirenz in the elderly with use in other age groups.

Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. It is important that you inform your health care professional of any prescriptionor nonprescription (OTC) medicine you are taking, especially if you are takingany of the following:

• Amprenavir (e.g., Agenerase)?Efavirenz may decrease the amountof this medicine in the body

• Astemizole (e.g., Hismanal) or
• Cisapride (e.g., Propulsid)?Efavirenz may increase the amountof these medicines in the body, which may cause cardiac arrythmias (irregularheartbeat)

• Ergot derivatives (e.g., Gerimal, Hydergine, Hydergine LC, Ergotrate,Methergine, Bellergal-S)?Efavirenz may increase the amount of thesemedicines in the body, which could lead to breathing problems

• Indinavir (e.g., Crixivan)?Efavirenz may decrease the amountof this medicine in the body

• Midazolam (e.g., Versed) or
• Triazolam (e.g., Halcion)?Efavirenz may increase the amountof these medicines in the body, which may lead to severe drowsiness

• Rifabutin (e.g., Mycobutin)?Efavirenz may decrease the amountof this medicine in the body

• Ritonavir (e.g., Norvir)?Taking efavirenz with this medicinemay increase the chance of side effects

• Saquinavir (e.g., Invirase)?Efavirenz may decrease the amountof this medicine in the body

• St. John's wort (Hypericum perforatum)(herbal supplement) ?Taking efavirenz with this herbal supplement maymake your body resistant to efavirenz and it may lose its effect.

• Voriconazole (e.g., VFend)?Efavirenz should not be taken withthis medicine. It can make voriconazole less effective for treating an infection.

• Warfarin (e.g., Coumadin)?Efavirenz may either increase ordecrease the amount of warfarin in the body

Other medical problems?The presence of other medicalproblems may affect the use of efavirenz. Make sure you tell your doctor ifyou have any other medical problems, especially:

• Alcohol or drug abuse history or
• Mental illness history?May increase the chance of having seriouspsychiatric side effects.

• Hepatitis B or C (history of) or
• Liver disease?Efavirenz may cause unwanted effects in the liver

• Seizures history?May increase chances of convulsions occurring

Proper Use of This Medicine

Take this medicine exactly as directed by your doctor. Do not takeit more often, and do not take it for a longer time than your doctor ordered.Also, do not stop taking this medicine without checking with your doctor first.

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

Efavirenz should be taken on an empty stomach because the amount of efavirenzabsorbed into the body may be increased when taken with food, which mightincrease the chance of side effects.

Take efavirenz at bedtime, especially during the first 2 to 4 weeks, tolessen central nervous system (CNS) side effects that may occur with thismedicine. These effects usually lessen after you have been taking this medicinefor awhile.

Dosing?The dose of efavirenz will be different fordifferent patients. Follow your doctor's orders or thedirections on the label. The following information includes only theaverage doses of efavirenz. If your dose is different,do not change it unless your doctor tells you to do so.

The number of capsules that you take depends on the strength of the medicine.

• For oral dosage form (capsules or tablets):
  • For treatment of HIV infection:
    • Adults?600 milligrams (mg) once a day, taken with other medicines.
    • Children 3 years of age and older (by weight)?
      • 10 to 15 kilograms (22 to 33 pounds) of body weight: 200 mg oncea day, taken with other medicines.
      • 15 to 20 kilograms (33 to 44 pounds) of body weight: 250 mg oncea day, taken with other medicines.
      • 20 to 25 kilograms (44 to 55 pounds) of body weight: 300 mg oncea day, taken with other medicines.
      • 25 to 32.5 kilograms (55 to 71.5 pounds) of body weight: 350 mg oncea day, taken with other medicines.
      • 32.5 to 40 kilograms (71.5 to 88 pounds) of body weight: 400 mg oncea day, taken with other medicines.
      • 40 kilograms (88 pounds) of body weight or over: 600 mg once a day,taken with other medicines.
    • Children up to 3 years of age?Use and dose must be determinedby your doctor.

Missed dose?If you miss a dose of this medicine, take it assoon as you remember. However, if it is almost time for your next dose, skipthe missed dose and go back to your regular dosing schedule. Do not doubledoses.

Storage?To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in otherdamp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

Efavirenzmay cause dizziness, difficulty in concentrating, or drowsiness. 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 dizzy or are not alert.

Check with your physician before taking efavirenz withalcohol or other medicines that affect the central nervous system (CNS). Theuse of alcohol or other medicines that affect the CNS with efavirenz may worsenthe side effects of this medicine, such as dizziness, poor concentration,drowsiness, unusual dreams, and trouble in sleeping. Some examplesof medicines that affect the CNS are antihistamines or medicine for hay fever,other allergies, or colds; sedatives, tranquilizers, or sleeping medicine;medicine for depression; medicine for anxiety; prescription pain medicineor narcotics; barbiturates; medicine for attention deficit and hyperactivitydisorder; medicine for seizures; muscle relaxants; or anesthetics, includingsome dental anesthetics.

Check with your doctor right away if you have serious psychiatric problems,such as severe depression, strange thoughts, or angry behavior.

Efavirenz does not decrease the risk of transmittingthe HIV infection to others through sexual contact or by contamination throughblood.

Women of childbearing potential should use two formsof birth control while taking this medicine, a barrier method of contraceptionand an oral or other hormonal method of contraception.

Check with your doctor promptly, if you develop a skin rash.

Side Effects of This Medicine

Along with its needed effects, a medicine maycause 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 as soon as possibleif any of the following side effects occur:

More common

Depression; skin rash or itching

Less common

Blood in urine; difficult or painfulurination; pain in lower back and/or side

Rare

Abdominal pain; changes in vision; blistering; clumsiness or unsteadiness; confusion; convulsions(seizures); cough; darkurine; delusions; doublevision; fainting; fast orpounding heartbeat; fever or chills; headache (severe and throbbing); hives; inappropriate behavior; loss of appetite; mood or mental changes (severe); muscle cramps or pain; nausea or vomiting; nerve pain; open sores; pain, tenderness, bluish color, or swellingof leg or foot; rapid weight gain; seeing, hearing, or feeling things that are not there; sense of constant movement of self or surroundings; sores, ulcers, or white spots in mouth or on lips; speech disorder; swelling and/or tenderness in upperabdominal or stomach area; swelling of hands, arms,feet, or legs; thoughts of suicide or attempts atsuicide; tightness in chest; tingling, burning, or prickling sensations; tingling,burning, numbness, or pain in the hands, arms, feet, or legs; tremor; troubled breathing; unusual tiredness; weight loss; wheezing; yellow eyes or skin

Incidence not known

Actions that are out of control; attack,assault, force; continuing vomiting; delusions of persecution, mistrust, suspiciousness, and/or combativeness; difficult or labored breathing; early appearance of redness or swelling of the skin; general feeling of tiredness or weakness; irritability; late appearance of rash with or without weepingblisters that become crusted, especially in sun-exposed areas of skin, mayextend to unexposed areas; light-colored stools; nervousness; neurosis; shortness of breath; stomach pain; talking, feeling, and acting with excitement

Other sideeffects may occur that usually do not need medical attention. These side effectsmay go away during treatment as your body adjusts to the medicine. However,check with your doctor if any of the following side effects continue or arebothersome:

More common

Diarrhea; dizziness; drowsiness; fatigue; headache; increased sweating; poorconcentration; trouble in sleeping

Less common or rare

Abnormally decreased sensitivity, particularly to touch; agitation or anxiety; belching; change in sense of taste or smell; dry mouth; excessive gas; false sense of well-being; flaking and falling offof skin; flushing; generalfeeling of discomfort; heartburn; indigestion; joint pain; lack of feeling or emotion; loss of hair; loss of memory; loss of sense of reality; mood changes; nervousness; pain; painful, red, hotor irritated hair follicles; ringing in the ears; stomach discomfort; unusualdreams; weakness

Incidence not known

Difficulty having a bowel movement (stool); discoloration of fingernails or toenails; large amountof triglyceride in the blood; malabsorption; muscular pain, tenderness, wasting or weakness; redistribution/accumulation of body fat; swelling of the breasts or breast soreness in both females and males

Other side effects not listed abovemay also occur in some patients. If you notice any other effects, check withyour doctor.