Tecovirimat: uses, dosing, side effects & brands
Tecovirimat is an orthopoxvirus vp37 envelope wrapping protein inhibitor sold in the U.S. under one brand, for smallpox. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Orthopoxvirus Vp37 Envelope Wrapping Protein Inhibitor
- Treats (across its forms)
- Smallpox
- Available as
- Capsule · Injectable
- Sold as
- Tpoxx
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How tecovirimat is dosed
From the FDA label for Tpoxx (application NDA214518). Other tecovirimat products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Pediatric and Adult Patients weighing 40 kg or more ( 2.3 ) (Oral Dosing): 40 kg to less than 120 kg: 600 mg of TPOXX every 12 hours for 14 days 120 kg or more: 600 mg of TPOXX every 8 hours for 14 days Pediatrics and adult patients weighing 13 kg or more and those who cannot swallow capsules ( 2.3 ) (Oral Dosing): TPOXX Capsules can be administered by carefully opening the number of capsule noted below and mixing and administering the entire contents in 30 mL of liquid (e.g., milk, chocolate milk) or soft food (e.g., apple sauce, yogurt): 13 kg to less than 25 kg: 200 mg (1 Capsule) of TPOXX every 12 hours for 14 days 25 kg to less than 40 kg: 400 mg (2 Capsules) of TPOXX every 12 hours for 14 days 40 kg to less than 120 kg: 600 mg (3 Capsules) of TPOXX every 12 hours for 14 days 120 kg or more: 600 mg (3 capsules) every 8 hours for 14 days Patients weighing 3 kg and above ( 2.5 ) (Intravenous Dosing): 3 kg to less than 35 kg: 6 mg/kg every 12 hours by intravenous infusion over 6 hours for up to 14 days 35 kg to less than 120 kg: 200 mg every 12 hours by intravenous infusion over 6 hours for up to 14 days 120 kg and above: 300 mg every 12 hours by intravenous infusion over 6 hours for up to 14 days Pediatric patients weighing 13 kg or more should be switched to TPOXX Capsules to complete the 14-day treatment course as soon as oral therapy can be tolerated. Administration…
Tecovirimat side effects
The most common adverse reactions are: TPOXX Capsules (incidence ≥ 2%): headache, nausea, abdominal pain, and vomiting. ( 6.1 ) TPOXX Injection (incidence ≥ 4%): administration site reactions and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact SIGA Technologies Inc. at 1-888-899-3472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of TPOXX has not been studied in patients with smallpox disease. TPOXX Clinical Trial (Oral Administration) The safety of TPOXX was evaluated in 359 healthy adult subjects ages 18-79 years in a Phase 3 clinical trial. Of the subjects who received at least one 600 mg dose of TPOXX, 59% were female, 69% were White, 28% were Black/African American, 1% were Asian, and 12% were Hispanic or Latino. Ten percent of the subjects who participated in the study were age 65 or older. Of these 359 subjects, 336 subjects received at least 23 of 28 doses of 600 mg TPOXX in a twice daily (every 12 hours) regimen for 14 days. Most Frequently Reported Adverse Reactions The most frequently reported adverse reactions were headache and nausea. Adverse…
Who shouldn’t take tecovirimat
TPOXX Capsules: None. TPOXX Injection: The excipient hydroxypropyl-β-cyclodextrin is eliminated through glomerular filtration. Therefore, TPOXX Injection is contraindicated in patients with severe renal impairment (defined as creatinine clearance below 30 mL/min) [see Warnings and Precautions ( 5.2 ) and Use in Specific Populations ( 8.6 )] . TPOXX capsules: None TPOXX injection: TPOXX Injection is contraindicated in patients with severe renal impairment (defined as creatinine clearance below 30 mL/min) ( 4 , 5.2 )
Tecovirimat drug interactions
Consult the full prescribing information prior to and during treatment for potential drug interactions. ( 5.1 , 7 , 12.3 ) 7.1 Effect of TPOXX on Other Drugs Tecovirimat is a weak inducer of cytochrome P450 (CYP)3A and a weak inhibitor of CYP2C8 and CYP2C19. However, the effects are not expected to be clinically relevant for most substrates of those enzymes based on the magnitude of interactions and the duration of treatment of TPOXX. Table 5 provides a listing of established or significant drug interactions and clinical recommendations for select sensitive substrates [see Warnings and Precautions ( 5.1 ) and Clinical Pharmacology ( 12.3 )] . Table 5: Significant Drug Interactions with Effect of TPOXX on Other Drugs a ↓ = decrease, ↑ = increase b These interactions have been studied in healthy adults. Concomitant Drug Class: Drug Name Effect on Concentration a Clinical Effect/Recommendation Blood Glucose-Lowering Agent: Repaglinide b ↑ repaglinide Monitor blood glucose and monitor for hypoglycemic symptoms in patients when TPOXX is co-administered with repaglinide [see Warnings and Precautions ( 5.1 )] . CNS Depressant: Midazolam b ↓ midazolam Monitor for effectiveness of midazolam. 7.2 Effect of Other drugs on TPOXX Co-administration of phosphate binders with tecovirimat increases tecovirimat bioavailability. Table 6 provides a listing of established drug interactions and clinical recommendations for select phosphate binders [see Clinical Pharmacology ( 12.3 )] . Table 6: Significant Drug Interactions with Effect of Other Drugs on TPOXX a ↑ = increase b These interactions have been studied in healthy adults. Concomitant Drug Class: Drug Name Effect on Concentration a Clinical Effect/Recommendation Phosphate Binders b : Calcium acetate Lanthanum carbonate Sevelamer carbonate Sucroferric oxyhydroxide ↑ tecovirimat Monitor for signs or symptoms of adverse effects when TPOXX is co-administered with phosphate binders [see Overdose ( 10 )] . 7.3 Drugs Without Clinically Significant Interactions With TPOXX Based on a drug interaction study, no clinically significant drug interactions have been observed when TPOXX is co-administered with bupropion, flurbiprofen, or omeprazole [see Clinical Pharmacology ( 12.3 )] . 7.4 Vaccine Interactions No vaccine-drug interaction studies have been performed in human subjects. Some animal studies have indicated that co-administration of TPOXX at the same time as live smallpox vaccine (vaccinia virus) may reduce the immune response to the vaccine. The clinical impact of this interaction on vaccine efficacy is unknown.
Every tecovirimat product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Tpoxx.
What tecovirimat pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| SIGA;ST246 | 200 mg | orange, black | capsule | — |
What people report to the FDA about tecovirimat
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 165 reports naming tecovirimat, and the FDA flagged 59% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- monkeypox27 reports
- immune reconstitution inflammatory syndrome16 reports
- acute kidney injury10 reports
- pancytopenia9 reports
- acidosis7 reports
- kounis syndrome7 reports
- encephalopathy6 reports
- nausea6 reports
Read these as a signal, not a rate. A report does not mean tecovirimat caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 26, 2026.
Related calculators
Frequently asked questions
What is tecovirimat?
TPOXX capsules and TPOXX injection contains tecovirimat, an inhibitor of the orthopoxvirus VP37 envelope wrapping protein. TPOXX (tecovirimat) capsules, for oral use are immediate release capsules containing tecovirimat monohydrate equivalent to 200 mg of tecovirimat for oral administration. The capsules include the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl methyl cellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium lauryl sulfate. The capsule shell is composed of gelatin, FD&C blue #1, FD&C red #3, FD&C yellow #6, and titanium dioxide. TPOXX (tecovirimat) injection, for intravenous use is a sterile, colorless to pale yellow solution free of visible particles that is intended for intravenous use following dilution.
What kind of drug is tecovirimat?
The FDA classifies tecovirimat as an orthopoxvirus vp37 envelope wrapping protein inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take tecovirimat with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run tecovirimat against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does tecovirimat come in?
Across the brands we track, tecovirimat is currently marketed as capsule and injectable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic tecovirimat?
We do not currently list a generic-labelled tecovirimat product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Tecovirimat: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/tecovirimat
- MLA
- “Tecovirimat: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/tecovirimat.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for tecovirimat on DailyMed (NIH) ↗.