Cobicistat, elvitegravir, emtricitabine and tenofovir is a combination medicine that is used to treat HIV (human immunodeficiency virus). HIV can cause acquired immunodeficiency syndrome (AIDS). This medicine is not a cure for HIV or AIDS.

Cobicistat, elvitegravir, emtricitabine, and tenofovir is for use in adults and children weighing at least 55 pounds (25 kilograms).

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

Some drugs should not be used with cobicistat, elvitegravir, emtricitabine, and tenofovir. Your treatment plan may change if you also use:

• alfuzosin;
• cisapride;
• oral midazolam, or triazolam;
• rifampin;
• sildenafil (Revatio, for treating pulmonary arterial hypertension);
• St. John's wort;
• antipsychotic medicine--lurasidone, pimozide;
• cholesterol medication--lomitapide, lovastatin, simvastatin;
• ergot medicine--dihydroergotamine, ergotamine, methylergonovine; or
• seizure medicine--carbamazepine, phenobarbital, phenytoin.

Cobicistat, elvitegravir, emtricitabine, and tenofovir is a complete combination treatment and should not be used with other antiviral medications, especially those that contain adefovir, cobicistat, elvitegravir, emtricitabine, lamivudine, ritonavir, or tenofovir: Atripla, Biktarvy, Cimduo, Combivir, Complera, Descovy, Epivir, Epzicom, Evotaz, Hepsera, Kaletra, Norvir, Odefsey, Prezcobix, Symfi, Symtuza, Technivie, Triumeq, Trizivir, Tybost, Viekira, and others.

Tell your doctor if you have ever had:

• hepatitis B or other liver problems; or
• kidney disease.

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. Ask your doctor about your risk.

This medicine may not work as well if you take it during pregnancy. Do not start taking the medicine if you are pregnant. Tell your doctor right away if you become pregnant.

If you plan to get pregnant, ask your doctor for another antiviral medicine to use during pregnancy. To prevent HIV in a newborn baby, use all medications to control your infection during pregnancy. Your name may be listed on an antiviral pregnancy registry.

If you do not plan to get pregnant, ask your doctor about using a non-hormonal birth control (condom, diaphragm, cervical cap, or contraceptive sponge) to prevent pregnancy. Cobicistat, elvitegravir, emtricitabine, and tenofovir can increase certain side effects when taken with hormonal birth control (pills, injections, implants, skin patches, vaginal rings).

Women with HIV should not breastfeed. The virus can pass to your baby in your breast milk.

Use Cobicistat, Elvitegravir, Emtricitabine, And Tenofovir (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• kidney problems--swelling, urinating less, feeling tired or short of breath;
• lactic acidosis--unusual muscle pain, trouble breathing, stomach pain, vomiting, irregular heart rate, dizziness, feeling cold, or feeling very weak or tired; or
• liver problems--nausea, upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Antiviral medicine can affect your immune system (even weeks or months after you've used this medicine). Tell your doctor if you have:

• signs of a new infection--fever, night sweats, swollen glands, cold sores, cough, wheezing, diarrhea, weight loss;
• trouble speaking or swallowing, problems with balance or eye movement, weakness or prickly feeling; or
• swelling in your neck or throat (enlarged thyroid), menstrual changes, impotence.

Common side effects may include:

• nausea; or
• diarrhea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Avoid taking an antacid within 2 hours before or 2 hours after you take cobicistat, elvitegravir, emtricitabine, and tenofovir. Some antacids can make it harder for your body to absorb this medicine.

Using this medicine will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Ask your doctor how to prevent HIV transmission during sex. Sharing drug or medicine needles is never safe.