An antiviral used for smallpox and mpox (monkeypox)
Tecovirimat
An antiviral medicine used to treat serious infections caused by pox viruses, such as smallpox and mpox (monkeypox).
What is Tecovirimat?
Tecovirimat is a specialist antiviral medicine used to treat serious infections caused by certain pox viruses, including smallpox and mpox (also called monkeypox). It works by stopping the virus from spreading from cell to cell within the body. It can be taken by mouth or, in some cases, given into a vein, and is generally well tolerated, with headache and nausea being among the more common side effects. It can interact with some other medicines, so the team checks your full medicines list. It is used under specialist supervision, usually for people with more serious or higher-risk infection.
Education and reference only. This is a plain-language guide to Tecovirimat — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Tecovirimat is an antiviral medicine used to treat infections caused by a group of viruses called orthopoxviruses, which includes smallpox and mpox (monkeypox). It is a specialist medicine, used in particular for people with more serious illness or who are at higher risk of complications. It can be given as capsules taken by mouth or, in some situations, as an infusion into a vein. It is prescribed and supervised by specialist services, often as part of managing outbreaks or treating individual cases that need antiviral treatment.
How it works
Tecovirimat blocks a protein the pox virus needs to wrap itself up and spread from one cell to the next inside the body. By stopping this step, it limits the virus's ability to spread, giving the immune system a better chance to bring the infection under control and helping to reduce the severity of illness. It does not work against viruses outside this pox family, which is why it is used specifically for smallpox and mpox. Because it targets a step in how the virus spreads, it is most useful as part of treating active infection under specialist care.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist antiviral used in the UK for serious infections caused by certain pox viruses, such as smallpox and mpox (monkeypox).
Practical use
How to take Tecovirimat
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take the capsules by mouth as prescribed, usually with food, which helps the medicine be absorbed; in some cases it is given into a vein.
- Finish the full course as advised, even if you feel better, to give the best chance of clearing the infection.
- Give the team a full list of your medicines, including contraception, as tecovirimat can interact with some of them.
- Tell the team about any new symptoms, such as troublesome headache or nausea, during treatment.
- Use it under specialist supervision and follow the team's advice on how long to take it.
Weighing it up
Advantages & disadvantages of Tecovirimat
Advantages
- A targeted antiviral for serious pox-virus infections such as smallpox and mpox.
- Generally well tolerated, with relatively mild common side effects.
- Can be taken by mouth, or given into a vein when that is more suitable.
Disadvantages
- Can interact with some other medicines, which needs checking.
- Headache and nausea are among the more common side effects.
- A specialist medicine used under supervision, not a routine treatment.
Practical use
Good to know
Tecovirimat is a targeted antiviral for pox-virus infections such as smallpox and mpox, and it is generally well tolerated, with headache and nausea being among the more common side effects. An important practical point is that it can interact with some other medicines, including by lowering the levels of certain drugs, so it is important to give the team a full list of everything you take, including contraception and other regular medicines, so they can check for problems. It can be taken by mouth, usually with food to help it be absorbed, or given into a vein when needed. It is used under specialist supervision, and the team will explain how long to take it and what to watch for. Finishing the course as advised is important, even if you start to feel better.
Who should not take it / use with caution
- People who have had a serious allergic reaction to tecovirimat should not take it.
- It is used with care alongside certain other medicines because of possible interactions.
- It should only be used under specialist supervision.
Monitoring
- Reviewing how the infection responds to treatment.
- Checking for side effects such as headache or nausea.
- Reviewing other medicines for possible interactions while it is being taken.
Side effects
- Headache, which is among the more common side effects.
- Nausea or other mild stomach upset.
- Less commonly, tiredness or other effects that should be reported to the team.
Key interactions
- It can lower the levels of some other medicines, which may make them less effective, so a full medicines list is important.
- Tell the team about contraception and any regular medicines, so they can check for interactions.
- Some medicines may need their timing or dose reviewed while you take tecovirimat.
Available as: Capsules taken by mouth, and a form given as an infusion into a vein.
Answers
Tecovirimat: frequently asked questions
What is tecovirimat used for?
It is an antiviral used to treat serious infections caused by certain pox viruses, including smallpox and mpox (monkeypox).
How does it work?
It blocks a protein the pox virus needs to spread from cell to cell, limiting the spread of the virus so the body can bring the infection under control.
How is it taken?
It is usually taken as capsules by mouth, often with food to help absorption, and in some situations it is given as an infusion into a vein.
Does it interact with other medicines?
Yes, it can interact with some medicines, including by lowering their levels, so give your team a full list of everything you take, including contraception.
Is it well tolerated?
It is generally well tolerated, with headache and nausea being among the more common side effects; tell your team about any troublesome symptoms.
Authoritative sources
- BNF
- NICE CKS
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