tecovirimat

Tecovirimat is an antiviral medication developed to treat infections caused by orthopoxviruses, including smallpox and related viruses such as monkeypox. It is marketed under names such as TPOXX and is produced for use in humans under regulatory oversight in several countries.

Mechanism of action and activity

Tecovirimat targets the p37 envelope protein, which is essential for the formation and egress of enveloped virions in orthopoxviruses. By inhibiting this step, the drug prevents production of the extracellular form of the virus, thereby limiting viral spread within the host. Laboratory studies show activity against variola virus (smallpox) and other members of the orthopoxvirus genus.

Medical use and regulatory status

In the United States, tecovirimat has been approved for the treatment of orthopoxvirus infections, including smallpox in adults and pediatric patients. The drug has also been used during mpox (monkeypox) outbreaks under regulatory authorizations or emergency use provisions in various jurisdictions. It is available in more than one formulation and is deployed in outbreak settings where orthopoxvirus infections are a concern.

Administration and dosing

Tecovirimat is available in oral capsule and intravenous forms. The typical adult dosing is 600 mg taken twice daily for 14 days, with pediatric dosing based on weight. Absorption of the oral form is enhanced when taken with a fatty meal, and the choice of route (oral or IV) depends on the patient’s ability to take medications by mouth.

Safety and considerations

Common adverse effects reported include headache, nausea, and abdominal pain. Serious adverse events are uncommon but may occur; patients should be monitored for allergic reactions. Pregnant or breastfeeding individuals should use tecovirimat only if clearly needed, with decisions guided by risk–benefit assessment. Drug interactions exist, and dosing may be adjusted in the context of coadministered therapies.