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TPOXX FDA Approval History

Last updated by Judith Stewart, BPharm on Nov 17, 2021.

FDA Approved: Yes (First approved July 13, 2018)
Brand name: TPOXX
Generic name: tecovirimat
Dosage form: Capsules
Company: SIGA Technologies, Inc.
Treatment for: Smallpox

TPOXX (tecovirimat) is an orthopoxvirus-specific antiviral indicated for the treatment of human smallpox disease.

  • Smallpox is a contagious, disfiguring and often deadly disease caused by the variola virus. Naturally occurring smallpox was eradicated worldwide by 1980 through a global immunization campaign. Samples of smallpox virus have been kept in laboratories for research purposes, leading to concerns of potential use as a biological warfare agent.
  • TPOXX works as an antiviral by inhibiting the orthopoxvirus VP37 envelope wrapping protein.
  • TPOXX is indicated for the treatment of human smallpox disease in adults and pediatric patients weighing at least 13 kg. The effectiveness of TPOXX for treatment of smallpox disease has not been determined in humans because adequate and well-controlled field trials have not been feasible, and inducing smallpox disease in humans to study the drug’s efficacy is not ethical. TPOXX efficacy may be reduced in immunocompromised patients based on studies demonstrating reduced efficacy in immunocompromised animal models.
  • TPOXX capsules are taken twice daily for 14 days. The capsules should be taken within 30 minutes after a full meal of moderate or high fat.
  • Common adverse reactions in healthy adult subjects (≥ 2%) include headache, nausea, abdominal pain, and vomiting.


What is TPOXX?

TPOXX is a prescription medicine used to treat smallpox disease caused by a type of virus called variola virus in adults and children who weigh at least 13 kg.

  • TPOXX may not work well in people who have a weakened immune system.
  • The effectiveness of TPOXX has been studied only in animals with orthopoxvirus diseases. There have been no human studies in people who have smallpox disease. The safety of TPOXX was studied in adults. There have been no studies of TPOXX in children 17 years of age and younger.

Before taking TPOXX, tell your healthcare provider about all of your medical conditions, including if you:

  • have diabetes.
  • are pregnant or plan to become pregnant. It is not known if TPOXX can harm your unborn baby. Tell your healthcare provider if you become pregnant during treatment with TPOXX.
  • are breastfeeding or plan to breastfeed. It is not known if TPOXX passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby.

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Some medicines interact with TPOXX. Keep a list of your medicines to show your healthcare provider and pharmacist.

  • You can ask your healthcare provider or pharmacist for a list of medications that interact with TPOXX.
  • Do not start taking a new medicine without telling your healthcare provider. Your healthcare provider can tell you if it is safe to take TPOXX with other medicines.

How should I take TPOXX?

  • Take TPOXX exactly as your healthcare provider tells you.
  • For adults and children who weigh at least 40 kg, take 3 capsules of TPOXX twice a day by mouth for 14 days.
  • TPOXX should be taken within 30 minutes after eating a full, fatty meal. Talk to your healthcare provider about examples of foods that you can eat that contain about 25 grams of fat. Always take TPOXX with food.
  • See the Instructions for Use that comes with your TPOXX for instructions on how to prepare and take a dose of TPOXX if:
    • your child weighs less than 40 kg, OR
    • you or your child have trouble swallowing TPOXX capsules.
  • Stay under the care of your healthcare provider during treatment with TPOXX.
  • Do not change your dose or stop taking TPOXX without talking to your healthcare provider.
  • It is important to take TPOXX for the full 14 day course of treatment. Do not miss or skip a dose of TPOXX.
  • If you take too much TPOXX, call your healthcare provider or go to the nearest hospital emergency room right away.

What are the possible side effects of TPOXX?

TPOXX may cause serious side effects, including:

  • Low blood sugar (hypoglycemia). Low blood sugar can happen when TPOXX is taken with repaglinide, a medicine used to treat type 2 diabetes. Tell your healthcare provider if you get any of the following symptoms of low blood sugar:
    • headache
    • drowsiness
    • hunger
    • feeling jittery or shaky
    • dizziness
    • confusion
    • sweating
    • weakness
    • fast heartbeat
    • irritability

The most common side effects of TPOXX include:

  • headache
  • nausea
  • stomach pain
  • vomiting

These are not all the possible side effects of TPOXX. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How should I store TPOXX?

  • Store TPOXX at room temperature between 68°F to 77°F (20°C to 25°C).
  • Keep TPOXX in its original container.

Keep TPOXX and all other medicines out of the reach of children.

General information about the safe and effective use of TPOXX.

Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use TPOXX for a condition for which it was not prescribed. Do not give TPOXX to other people, even if they have the same symptoms that you have. It may harm them. You can ask your pharmacist or healthcare provider for information about TPOXX that is written for health professionals.

What are the ingredients in TPOXX?

Active ingredient: tecovirimat

Inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl methyl cellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium lauryl sulfate. The capsule shell is made of gelatin, FD&C blue #1, FD&C red #3, FD&C yellow #6, and titanium dioxide.

Development Timeline for TPOXX

Jul 13, 2018Approval  FDA Approves TPOXX (tecovirimat) as the First Drug for the Treatment of Smallpox
May  1, 2018SIGA Technologies Announces Favorable Outcome of Advisory Committee In Support of TPOXX
Feb  7, 2018SIGA Technologies Announces FDA Accepts NDA and Grants Priority Review for Oral TPOXX to Treat Smallpox
Dec 11, 2017SIGA Technologies Announces FDA Submission of its New Drug Application for oral TPOXX (tecovirimat) to Treat Smallpox

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.