Drug information

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Brincidofovir
Other Names
Tembexa, CMX001
Drug Class
Antiviral (Orthopoxvirus Nucleotide Analog DNA Polymerase Inhibitor)

What is brincidofovir? What is brincidofovir?

What is brincidofovir?

Brincidofovir is an antiviral prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of smallpox in adults and children, including newborn infants. (Smallpox is a disease caused by the variola virus, a member of a group of viruses called orthopoxviruses. Since 1980, smallpox has been considered eradicated worldwide.)

Although brincidofovir is FDA-approved only for smallpox treatment, it may also be used to treat another type of orthopoxvirus infection called mpox. Brincidofovir may be obtained for mpox treatment through a request by a physician to FDA. (This type of request is known as an emergency expanded access request or emergency IND request.)

Mpox can be an opportunistic infection (OI) of HIV. An OI is an infection that occurs more frequently or is more severe in people with weakened immune systems—such as people with HIV—than in people with healthy immune systems. To learn more about OIs, read the HIVinfo What is an Opportunistic Infection? fact sheet.

To learn more about how to take care of yourself if you have mpox and the use of brincidofovir for treating mpox, including whether or not brincidofovir may be right for you, visit the Centers for Disease Control and Prevention (CDC) webpage Monkeypox: What to Do If You Are Sick.

How is brincidofovir used in people with HIV? How is brincidofovir used in people with HIV?

How is brincidofovir used in people with HIV?

The Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents With HIV include recommendations on the use of brincidofovir to treat mpox in adults. Additionally, the Guidelines for the Prevention and Treatment of Opportunistic Infections in Children With and Exposed to HIV reference the Centers for Disease Control and Prevention's (CDC) Clinical Care webpage, which includes links to related pages containing information on the use of brincidofovir to treat mpox in children and adolescents and in people with HIV.

The recommended uses may not always be consistent with FDA-approved uses of brincidofovir. See the Adult Guidelines and the CDC’s Clinical Care webpage and related pages for complete information on recommended uses of brincidofovir in adults and children with HIV. Brincidofovir may have other recommended uses not listed above.

What should I tell my health care provider before taking brincidofovir? What should I tell my health care provider before taking brincidofovir?

What should I tell my health care provider before taking brincidofovir?

Before taking brincidofovir, tell your health care provider:

  • If you are allergic to brincidofovir or any other medicines.
  • About any medical conditions you have or have had, including liver problems or a weakened immune system.
  • About anything that could affect your ability to take medicines, such as difficulty swallowing or remembering to take pills.
  • If you are pregnant or plan to become pregnant. Brincidofovir should not be used during pregnancy. Talk to your health care provider about the risks of taking brincidofovir during pregnancy.
  • If you are breastfeeding or plan to breastfeed. For mothers with HIV in the United States, the Guideline recommends speaking with your health care provider to discuss options for feeding your baby. Mothers with suppressed viral load have a less than 1% chance of transmitting HIV to their baby via their own milk. Although most medicines are safe to use while breastfeeding, some medicines should be avoided. Always let your health care provider know about all the medicines and supplements you are using before you start breastfeeding.
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Brincidofovir may affect the way other medicines or products work, and other medicines or products may affect how brincidofovir works. Ask your health care provider if there are interactions between brincidofovir and the other medicines you take.

How should I take brincidofovir? How should I take brincidofovir?

How should I take brincidofovir?

Take brincidofovir according to your health care provider’s instructions. Your health care provider will tell you how much brincidofovir to take and when to take it. Before you start brincidofovir and each time you get a refill, read any printed information that comes with your medicine.

What side effects can brincidofovir cause? What side effects can brincidofovir cause?

What side effects can brincidofovir cause?

Brincidofovir may cause side effects that can be mild or serious. To learn about possible side effects of brincidofovir, see the FDA drug labels for brincidofovir tablet (film coated) and suspension or talk to your health care provider or pharmacist. Tell your health care professional if you have any side effect that bothers you or that does not go away. Your health care professional may be able to tell you about ways to prevent or reduce some side effects.

How should brincidofovir be stored? How should brincidofovir be stored?

How should brincidofovir be stored?

  • Store brincidofovir tablets and oral suspension at room temperature, 68°F to 77°F (20°C to 25°C). Do not freeze the oral suspension.
  • Keep brincidofovir in the container that it came in and keep the container tightly closed.
  • Do not use brincidofovir if the original seal over the container opening is broken or missing.
  • Throw away brincidofovir that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep brincidofovir and all medicines out of reach of children.

Where can I find more information about brincidofovir? Where can I find more information about brincidofovir?

Where can I find more information about brincidofovir?

Last Reviewed: November 17, 2025