Mytesi is used in adults to treat diarrhea that may be caused by taking antiviral medicine to treat HIV (human immunodeficiency virus). This medicine is not for use in treating diarrhea that is caused by an infection.

Mytesi is not a treatment for HIV.

Mytesi may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before you start treatment with Mytesi, your doctor may perform medical tests to make sure you do not have infectious diarrhea.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Swallow the tablet whole and do not crush, chew, or break it.

You may take Mytesi with or without food.

Store at room temperature away from moisture and heat.

Tell your doctor if you are sick with diarrhea and vomiting or other symptoms of infection.

It is not known whether Mytesi will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

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

Mytesi is not approved for use by anyone younger than 18 years old.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

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

Mytesi may cause serious side effects. Call your doctor at once if you have:

• dark urine, jaundice (yellowing of the skin or eyes);

• wheezing, chest tightness, trouble breathing; or

• worsening diarrhea.

Common side effects of Mytesi may include:

• abnormal blood tests;

• gas; or

• cold symptoms such as stuffy nose, sneezing, cough.

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.