Mytesi (Crofelemer) for HIV

Mytesi (crofelemer) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to relieve symptoms of noninfectious diarrhea in adults with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) who are taking antiretroviral therapy.

How Mytesi Works and How It’s Taken

Mytesi is an antidiarrheal medicine. It works by blocking certain channels in the gut that control the movement of chloride and water. This helps reduce the extra chloride and water loss that happens with diarrhea.

Doctors prescribe Mytesi when adults with HIV/AIDS who are taking antiretroviral therapy have noninfectious diarrhea.

HIV-1 is a type of HIV that can cause AIDS.

Mytesi comes as a tablet taken by mouth. It can be taken with or without food. The tablets should be swallowed whole and should not be crushed or chewed.

Typical Dosing for HIV

The recommended adult dose of Mytesi is 125 milligrams taken by mouth two times a day.

Before starting Mytesi, a healthcare provider should rule out an infection as the cause of diarrhea. Mytesi is not used to treat infectious diarrhea.

This information is based on prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Mytesi Side Effects

In clinical studies of Mytesi, the most common side effects occurred in about 3 percent to 6 percent of people. These include:

Upper respiratory tract infection (a “common cold” type infection)
Bronchitis (inflammation of the airways in the lungs)
Cough
Flatulence (gas)
Increased bilirubin (a change in a blood test that can be related to the liver)

Serious Side Effects and Warnings

Infectious diarrhea — Mytesi does not treat diarrhea caused by an infection. Starting Mytesi without treating the infection could allow the illness to get worse.

Get medical help right away if you think you are having a serious reaction.

How To Save on Mytesi

The Mytesi Copay Savings Start Card Program may help eligible people with commercial insurance pay as little as $0, subject to program restrictions.

The THERA patient support program also offers services to help you start and stay on treatment.

To learn more, visit Mytesi Savings and Support or call 833-238-4372.

What To Know Before Taking Mytesi

Before starting Mytesi, your healthcare provider should check whether an infection is causing your diarrhea. Mytesi is not used to treat infectious diarrhea.

Tell your doctor if you have any allergies to crofelemer or any ingredients in Mytesi.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

If you miss a dose, take it as soon as you remember. Do not take two doses at the same time.

If you are pregnant, Mytesi is expected to result in very little fetal exposure because only a small amount of the medicine is absorbed into the body. Talk with your doctor about the risks and benefits of using Mytesi during pregnancy.

If you have HIV-1, you should not breastfeed because HIV-1 can be passed to your baby. The prescribing information also says people taking Mytesi should not breastfeed.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Mytesi for noninfectious diarrhea?

In a study of 374 adults with HIV who were taking stable antiretroviral therapy and had diarrhea for at least one month, 18 percent of people taking Mytesi 125 milligrams two times a day had a clinical response, compared with 8 percent of people taking a placebo (an inactive treatment).

A clinical response meant having two or fewer watery bowel movements per week during at least two of the four treatment weeks.

Of the 24 people who responded to Mytesi, 22 continued into the longer follow-up period. Of those, 16 were still responding at the end of month 3, and 14 were still responding at the end of month 5.

How long does Mytesi take to work for noninfectious diarrhea?

The main study measured response during a 31-day treatment period. It does not give an exact average number of days for Mytesi to start working.

Should I take Mytesi for noninfectious diarrhea if I have an infection?

Mytesi is used to relieve noninfectious diarrhea in adults with HIV/AIDS who are taking antiretroviral therapy.

Before starting Mytesi, your healthcare provider should rule out an infection as the cause of your diarrhea. Mytesi is not used to treat infectious diarrhea. If an infection is causing your diarrhea and it is not treated properly, the illness may get worse.