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TPOXX Side Effects

Generic name: tecovirimat

Medically reviewed by Last updated on Sep 16, 2023.

Note: This document contains side effect information about tecovirimat. Some dosage forms listed on this page may not apply to the brand name TPOXX.

Applies to tecovirimat: oral capsule.

Serious side effects of TPOXX

Along with its needed effects, tecovirimat (the active ingredient contained in TPOXX) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking tecovirimat:

Less common

Other side effects of TPOXX

Some side effects of tecovirimat may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

For Healthcare Professionals

Applies to tecovirimat: intravenous solution, oral capsule.


The safety of this drug has not been studied in patients with smallpox disease. The reported adverse reactions are for studies in healthy subjects.[Ref]


Frequency reported as less than 2%: Palpable purpura, rash, pruritic rash, facial redness, facial swelling and pruritus[Ref]


Common (1% to 10%): Nausea, abdominal pain, vomiting

Frequency reported as less than 2%: Dry mouth, dyspepsia, eructation, oral paresthesia[Ref]


Intravenous administration:

Very common (10% or more): Infusion site pain (73%), swelling (39%), erythema (23%), extravasation (19%)[Ref]


Frequency reported as less than 2%: Arthralgia, osteoarthritis[Ref]


Frequency reported as less than 2%: Depression, dysphoria, irritability, panic attack[Ref]


Frequency reported as less than 2%: Oropharyngeal pain[Ref]

Nervous system

Very common (10% or more): Headache (up to 15%)

Frequency reported as less than 2%: Migraine, disturbance in attention, dysgeusia, paresthesia[Ref]

Frequently asked questions


1. Product Information. Tpoxx (tecovirimat). SIGA Technologies, Inc.

Further information

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

Some side effects may not be reported. You may report them to the FDA.