Efavirenz, emtricitabine, and tenofovir is an antiviral medication that prevents human immunodeficiency virus (HIV) from reproducing in your body.

Efavirenz, emtricitabine, and tenofovir treats HIV, which causes acquired immunodeficiency syndrome (AIDS). This medication is not a cure for HIV or AIDS.

Efavirenz, emtricitabine, and tenofovir may also be used for purposes not listed in this medication guide.

Do not use efavirenz, emtricitabine, and tenofovir if you are pregnant. It could harm the unborn baby.

Do not take this medication if you are also taking cisapride (Propulsid), midazolam (Versed), triazolam (Halcion), St. John's wort, voriconazole (Vfend), or an ergot medicine such as dihydroergotamine (D.H.E. 45, Migranal), ergonovine (Ergotrate), ergotamine (Ergomar), or methylergonovine (Methergine). Do not take this medication with other medicines that also contain efavirenz, emtricitabine, or tenofovir (Complera, Sustiva, Emtriva, Truvada, Viread), or lamivudine (Combivir, Epivir, Epzicom, Trizivir).

There are many other drugs that can cause serious or life-threatening medical problems if you take them together with efavirenz, emtricitabine, and tenofovir. Tell your doctor about all medications you use.

Some people develop lactic acidosis while taking efavirenz, emtricitabine, and tenofovir. Early symptoms may get worse over time and this condition can be fatal. Get emergency medical help if you have even mild symptoms such as: muscle pain or weakness, numb or cold feeling in your arms and legs, trouble breathing, stomach pain, nausea with vomiting, fast or uneven heart rate, dizziness, or feeling very weak or tired.

Efavirenz, emtricitabine, and tenofovir can cause severe or fatal liver problems. Call your doctor at once if you have symptoms such as nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

You should not take this medication if you are allergic to efavirenz (Sustiva), emtricitabine (Emtriva), or tenofovir (Viread), or if you are taking any of the following drugs:

• cisapride (Propulsid);

• midazolam (Versed) or triazolam (Halcion);

• St. John's wort;

• voriconazole (Vfend);

• an ergot medicine such as dihydroergotamine (D.H.E. 45, Migranal), ergonovine (Ergotrate), ergotamine (Ergomar), or methylergonovine (Methergine);

• lamivudine (Combivir, Epivir, Epzicom, or Trizivir); or

• any other medicines that also contain efavirenz, emtricitabine, or tenofovir (such as Complera, Sustiva, Emtriva, Truvada, or Viread).

To make sure you can safely take this medication, tell your doctor if you have any of these other conditions:

• liver or kidney disease;

• a history of mental illness, use of antipsychotic medication, or injection drug use;

• epilepsy or other seizure disorder;

• osteopenia (low bone mineral density); or

• hepatitis B or C infection.

FDA pregnancy category D. Do not use this medication if you are pregnant. It could harm the unborn baby. Tell your doctor if you become pregnant during treatment. Use two forms of birth control, including a barrier form (such as a condom or diaphragm with spermicide) while you are using this medication and for at least 12 weeks after your treatment ends.

HIV can be passed to your baby if you are not properly treated during pregnancy. Take all of your HIV medicines as directed to control your infection.

Women with HIV or AIDS should not breast-feed a baby. Even if your baby is born without HIV, the virus may be passed to the baby in your breast milk.

Some people develop a life-threatening condition called lactic acidosis while taking efavirenz, emtricitabine, and tenofovir. You may be more likely to develop lactic acidosis if you are overweight or have liver disease, if you are a woman, or if you have taken HIV or AIDS medications for a long time. Talk with your doctor about your individual risk.