A single-infusion antiviral for influenza (flu)
Peramivir
An antiviral for influenza given as a single infusion into a vein when an oral medicine cannot be used.
What is Peramivir?
Peramivir is an antiviral medicine used to treat influenza (flu). It is given as a single infusion into a vein, which makes it useful when a person cannot take an oral flu antiviral, for example if they cannot swallow or absorb medicines. It works by stopping the flu virus from spreading between cells, and it works best when started early after symptoms begin. It is generally well tolerated, with diarrhoea among the more common effects, and, rarely, allergic or skin reactions can occur. It is used under medical, usually hospital, supervision.
Education and reference only. This is a plain-language guide to Peramivir — 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
Peramivir is an antiviral medicine used to treat influenza, the illness caused by the flu virus. Unlike the more familiar flu antivirals taken by mouth, peramivir is given as a single infusion into a vein. This makes it particularly useful for people who cannot take or absorb an oral antiviral, such as those who are very unwell or unable to swallow. It belongs to the same family of flu antivirals that block an enzyme the virus needs to spread. It is a specialist medicine, used under medical supervision, usually in hospital.
How it works
Peramivir blocks an enzyme on the surface of the flu virus called neuraminidase, which the virus normally uses to break free from infected cells and spread to new ones. By blocking this enzyme, peramivir stops the virus spreading through the body, so the immune system can bring the infection under control and symptoms ease sooner. Like other flu antivirals, it works best when started early after symptoms begin, while the virus is still multiplying. Being given as a single infusion into a vein means the full treatment can be delivered in one go.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist antiviral used in the UK against influenza, given as a single infusion into a vein when an oral antiviral is not suitable.
Practical use
How to take Peramivir
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given as a single infusion into a vein by healthcare staff; you do not take it yourself.
- It works best when started as early as possible after flu symptoms begin, so prompt treatment matters.
- Tell the team about any kidney problems, as this may be taken into account when planning treatment.
- Report any rash, blistering, swelling or difficulty breathing straight away, as these can signal a reaction.
- Continue the supportive care the team advises, such as rest and fluids, alongside the antiviral.
Weighing it up
Advantages & disadvantages of Peramivir
Advantages
- Given as a single infusion, so the full treatment is delivered in one go.
- Useful when a person cannot take or absorb an oral flu antiviral.
- Generally well tolerated, working against the flu virus when started early.
Disadvantages
- Must be given into a vein by healthcare staff rather than taken at home as a tablet.
- Works best only if started early after symptoms begin.
- Rarely, serious skin or allergic reactions can occur.
Practical use
Good to know
The main thing that sets peramivir apart is that it is given as a single infusion into a vein rather than as tablets or liquid by mouth, which makes it a helpful option when someone cannot take or keep down an oral flu antiviral. As with all flu antivirals, timing matters: it works best when started as early as possible after flu symptoms appear, while the virus is still multiplying. It is generally well tolerated, with diarrhoea among the more commonly reported effects. Rarely, serious skin or allergic reactions can occur, so any rash, blistering, swelling or difficulty breathing should be reported straight away. It is a specialist medicine given under medical supervision, and the team will take into account kidney function when planning treatment.
Who should not take it / use with caution
- People who have had a serious allergic reaction to peramivir should not be given it.
- It is used with care in people whose kidneys are not working well, who may need treatment adjusted.
- It is used under medical supervision, usually in hospital, so the team can assess whether it is right for you.
Monitoring
- Reviewing how the flu illness responds to treatment.
- Watching for allergic or skin reactions during and after the infusion.
- Taking kidney function into account and checking blood tests where appropriate.
Side effects
- Diarrhoea, which is among the more commonly reported effects.
- Nausea or stomach upset in some people.
- Changes in some blood tests, such as liver blood tests, picked up by monitoring.
- Rarely, serious skin or allergic reactions, which need urgent medical attention.
Key interactions
- Tell the team about all your medicines, although peramivir has relatively few major interactions.
- Live flu vaccines may be affected by flu antivirals, so the team will advise on timing if relevant.
- Your kidney function may affect dosing, so the team reviews this when planning treatment.
Available as: A solution given as a single infusion into a vein, under medical supervision.
Answers
Peramivir: frequently asked questions
What is peramivir used for?
It is an antiviral used to treat influenza (flu), given as a single infusion into a vein, which is useful when someone cannot take an oral flu antiviral.
How is it given?
It is given as a single infusion into a vein by healthcare staff, usually in hospital, rather than as tablets or liquid by mouth.
When does it work best?
Like other flu antivirals, it works best when started as early as possible after flu symptoms begin, while the virus is still multiplying.
Is it well tolerated?
Yes, it is generally well tolerated, with diarrhoea among the more common effects; rarely, serious skin or allergic reactions can occur and need urgent attention.
Why might it be chosen over a tablet?
Because it is given into a vein, it is helpful for people who cannot take or keep down an oral flu antiviral, such as those who are very unwell or cannot swallow.
The wider class
About Antiviral for influenza (into a vein)
Peramivir belongs to the antiviral for influenza (into a vein) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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