Skip to Content


Medically reviewed by Last updated on Aug 7, 2020.


(TEK oh VIR i mat)

Index Terms

  • Tpoxx

Pharmacologic Category

  • Antiviral Agent


Tecovirimat inhibits the activity of the orthopoxvirus VP37 protein and blocks its interaction with cellular Rab9 GTPase and TIP47, preventing formation of egress-competent enveloped virions (necessary for dissemination of virus).


Vd (Vz/F): 1,030 L


Hydrolysis of the amide bond and glucuronidation (UGT1A1, UGT1A4)


Urine (73%, predominantly metabolites); feces (23%, predominantly as unchanged drug)

Time to Peak

4 to 6 hours

Half-Life Elimination

20 hours

Protein Binding

77% to 82%

Use: Labeled Indications

Smallpox: Treatment of human smallpox disease caused by variola virus in adults and pediatric patients weighing ≥13 kg.

Limitations of use: 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.


There are no contraindications listed in the manufacturer's labeling.

Dosing: Adult

Smallpox: Oral: 600 mg twice daily for 14 days

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Smallpox disease: Children and Adolescents: Oral:

13 to <25 kg: 200 mg twice daily for 14 days

25 to <40 kg: 400 mg twice daily for 14 days

≥40 kg: 600 mg twice daily for 14 days


Oral: Administer ≤30 minutes after a full meal of moderate or high fat (about 25 g of fat). For patients who cannot swallow capsules, capsules may be opened and entire contents mixed with 30 mL of liquid (eg, milk, chocolate milk, infant formula) or soft food (eg, applesauce, yogurt); powder may not dissolve completely. Administer entire mixture within 30 minutes after preparation.

Dietary Considerations

Take ≤30 minutes after a full meal of moderate or high fat (about 25 g of fat).


Store at 20°C to 25°C (68°F to 77°F); excursions permitted 15°C to 30°C (59°F to 86°F).

Drug Interactions

CloBAZam: CYP2C19 Inhibitors (Weak) may increase serum concentrations of the active metabolite(s) of CloBAZam. CYP2C19 Inhibitors (Weak) may increase the serum concentration of CloBAZam. Monitor therapy

CloZAPine: CYP3A4 Inducers (Weak) may decrease the serum concentration of CloZAPine. Monitor therapy

Fosphenytoin-Phenytoin: CYP2C19 Inhibitors (Weak) may increase the serum concentration of Fosphenytoin-Phenytoin. Monitor therapy

Midazolam: Tecovirimat may decrease the serum concentration of Midazolam. Monitor therapy

NiMODipine: CYP3A4 Inducers (Weak) may decrease the serum concentration of NiMODipine. Monitor therapy

Repaglinide: CYP2C8 Inhibitors (Weak) may increase the serum concentration of Repaglinide. Monitor therapy

Selpercatinib: CYP3A4 Inducers (Weak) may decrease the serum concentration of Selpercatinib. Monitor therapy

Smallpox Vaccine Live: Tecovirimat may diminish the therapeutic effect of Smallpox Vaccine Live. Monitor therapy

Tacrolimus (Systemic): CYP3A4 Inducers (Weak) may decrease the serum concentration of Tacrolimus (Systemic). Monitor therapy

Ubrogepant: CYP3A4 Inducers (Weak) may decrease the serum concentration of Ubrogepant. Management: Use an initial ubrogepant dose of 100 mg and second dose (if needed) of 100 mg when used with a weak CYP3A4 inducer. Consider therapy modification

Adverse Reactions

>10%: Central nervous system: Headache (12%)

1% to 10%:

Cardiovascular: Increased heart rate (<2%)

Central nervous system: Abnormal electroencephalogram (<2%), chills (<2%), depression (<2%), disturbance in attention (<2%), dysphoria (<2%), irritability (<2%), malaise (<2%), migraine (<2%), pain (<2%), panic attack (<2%), paresthesia (<2%)

Dermatologic: Cheilosis (<2%), facial erythema (<2%), facial swelling (<2%), pruritic rash (<2%), pruritus (<2%), skin rash (<2%)

Endocrine & metabolic: Increased thirst (<2%)

Gastrointestinal: Nausea (5%), abdominal pain (2%), vomiting (2%), dysgeusia (<2%), dyspepsia (<2%), eructation (<2%), oral paresthesia (<2%), xerostomia (<2%)

Hematologic & oncologic: Decreased hematocrit (<2%), decreased hemoglobin (<2%), purpuric rash (palpable: <2%)

Neuromuscular & skeletal: Arthralgia (<2%), osteoarthritis (<2%)

Respiratory: Oropharyngeal pain (<2%)

Miscellaneous: Fever (<2%)

Frequency not defined: Gastrointestinal: Diarrhea, mild gastric distress


Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Immunocompromised patients: Efficacy may be reduced (based on studies in immunocompromised animal models).

Monitoring Parameters

Blood glucose, symptoms of hypoglycemia (when coadministered with repaglinide)

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. Pregnant patients were not included in pharmacokinetic studies (Grosenbach 2018).

Smallpox infection is more severe in pregnant patients; transmission to the fetus may occur (Fenner 1988).

Patient Education

What is this drug used for?

• It is used to treat smallpox.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Headache

• Nausea

• Vomiting

• Abdominal pain

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

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

Related questions

More about tecovirimat

Consumer resources

Professional resources

Other brands: TPOXX

Related treatment guides