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Efavirenz

Antiretroviral

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What is efavirenz?

Efavirenz (also called Sustiva® or DMP-266) is used to treat infection caused by the human immunodeficiency virus (HIV). This medicine is one of a group called non-nucleoside reverse transcriptase inhibitors (NNRTIs). Efavirenz can slow down how soon you will see symptoms or slow the damage caused by HIV, but it cannot cure HIV infection. This medicine is offered as 50-mg, 100-mg, and 200-mg capsules. A liquid form of efavirenz may also be used.

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Possible side effects

  • Headache
  • Unusual dreams
  • Feeling dizzy or drowsy
  • Trouble concentrating
  • Diarrhea
  • Rash

    These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

Symptoms of an allergic reaction include: rash, hives, itching, chills, fever, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck.

Not all patients who take efavirenz will experience these side effects. Common side effects are bolded, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

Find more information on side effects.

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Tips for patients and families

Be sure to discuss all questions and instructions with your doctor or pharmacist. 

  • Store efavirenz capsules and liquid at room temperature.
  • Women must not become pregnant while they are taking efavirenz. Women who are old enough to become pregnant should talk to their doctor, nurse, or pharmacist about methods of birth control that work well. If you use pills for birth control, you should use a second method of birth control (such as a condom) while taking efavirenz.
  • Efavirenz may affect the way other medicines work. These medicines include:
    • Clarithromycin
    • Indinavir
    • Oral contraceptives (birth control pills)
    • Rifabutin
    • Saquinavir.
  • Some medicines can affect the way efavirenz works. These medicines include:
    • Rifampin
    • St. John’s wort

      Always tell the doctor if you are taking these medicines, or if you start taking any new medicines while you are taking efavirenz.

Drug at Home:

  • This medicine is taken once a day, usually at bedtime. It must be taken every day.
  • Efavirenz can be taken with or without food. Taking the medicine right after you have eaten a meal may help prevent upset stomach
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Always check the medication label. Many medicines look the same. Do not take any new medicine, including over-the counter medicines or supplements, without checking with your doctor or pharmacist. Talk to your doctor or pharmacist about what to do in the case of a missed dose, allergic reaction, or medical emergency. 

This information is not intended to be a complete guide and is not a substitute for talking with your provider. Medicine names, appearance, formulas, or availability may vary by clinic location. Always follow the instructions given by your care team.

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