An antivenom for UK adder (Vipera berus) bites
European viper antivenom
An antivenom given in hospital to reverse the effects of a serious bite from the UK adder.
What is European viper antivenom?
European viper antivenom is a specialist hospital treatment for serious bites from the adder (Vipera berus), the only venomous snake native to the UK. It works by binding to and neutralising the venom, reversing its effects such as severe swelling, low blood pressure and other reactions. Because it is made from animal blood, it can cause serious allergic reactions, including anaphylaxis, so it is given in hospital with close monitoring and emergency treatment to hand. It is reserved for bites causing significant envenoming, not every adder bite, and the decision to use it is made by the medical team.
Education and reference only. This is a plain-language guide to European viper antivenom — 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
European viper antivenom is a medicine used to treat bites from the European adder (Vipera berus), the only venomous snake native to Britain. It is an antivenom, made from the blood of animals that have been immunised against adder venom, and it contains antibodies that neutralise the venom. It is given in hospital, usually as an infusion into a vein, for people who have signs of significant envenoming, such as marked swelling, low blood pressure or other serious effects. Not every adder bite needs antivenom, so the medical team decides based on how the person is affected. Because it is an animal product, it can trigger allergic reactions and is given with care.
How it works
When an adder bites, it injects venom that can cause swelling spreading up the limb, pain, low blood pressure, vomiting and other reactions. European viper antivenom contains antibodies that bind to the venom and neutralise it, stopping it from causing further harm and helping the body recover. Because it is made from animal blood, the body can sometimes react to it as a foreign substance, which is why allergic reactions are a key risk. It is given when the effects of the venom are significant enough that neutralising it is worthwhile, with the benefits weighed against the risk of a reaction.
Company & origin
Originated / developed by: Specialist supply.
A specialist hospital treatment used in the UK for bites from the adder (Vipera berus), the only venomous snake native to Britain.
Practical use
How to take European viper antivenom
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given in hospital by the medical team, usually as an infusion into a vein, not something used at home.
- It is reserved for bites causing significant effects, not every adder bite, with the team deciding when it is needed.
- After a bite, keep the bitten limb still and low, remove rings and tight clothing, and get to hospital.
- You will be watched closely during and after treatment for any allergic reaction.
- Tell the team about any allergies and any previous antivenom or antiserum you have had.
Weighing it up
Advantages & disadvantages of European viper antivenom
Advantages
- Neutralises adder venom and can reverse serious effects such as spreading swelling and low blood pressure.
- Can speed recovery and reduce harm in people with significant envenoming.
- Provides a targeted treatment for the only venomous snake native to the UK.
Disadvantages
- Made from animal blood, so it can cause serious allergic reactions, including anaphylaxis.
- Must be given in hospital with close monitoring and emergency treatment available.
- Not needed for every bite, so its use depends on how badly the venom is affecting the person.
Practical use
Good to know
The most important thing to understand is that, because the antivenom is made from animal blood, it can cause serious allergic reactions, including life-threatening anaphylaxis, so it is always given in hospital where breathing and blood pressure can be supported and emergency treatment is immediately available. It is not used for every adder bite; many bites cause only local effects and are managed with observation and supportive care, while antivenom is reserved for significant envenoming such as spreading swelling, low blood pressure or systemic effects. Anyone bitten by an adder should keep the bitten limb still, remove rings or tight items, and get to hospital, as effects can develop over hours. The medical team monitors closely after a bite and decides if and when antivenom is needed, and watches for allergic reactions during and after it is given.
Who should not take it / use with caution
- It is used with caution in people with known allergy to it or to animal serum, where the risk is weighed against the severity of the bite.
- It is only given in hospital where severe allergic reactions can be treated immediately.
- The decision to use it is made by the medical team based on the signs of envenoming.
Monitoring
- Close watching during and after the infusion for allergic reactions, including breathing and blood pressure.
- Monitoring the bitten limb and the person's overall condition for the effects of the venom.
- Watching for delayed serum sickness in the days after treatment.
Side effects
- Serious allergic reactions, including anaphylaxis, which can happen during the infusion and need emergency treatment.
- A delayed reaction called serum sickness, with fever, rash and joint pains days later.
- Reactions where the drip is given, fever or chills.
Key interactions
- There are few routine medicine interactions, but tell the team about all medicines and any allergies.
- It is given alongside supportive care such as fluids and pain relief as needed.
- Any previous reaction to antivenom or animal serum should be reported, as it affects how it is used.
Available as: A solution given as an infusion into a vein in hospital.
Answers
European viper antivenom: frequently asked questions
What is European viper antivenom used for?
It is a hospital treatment for serious bites from the UK adder (Vipera berus); it neutralises the venom and reverses effects such as severe swelling and low blood pressure.
Does every adder bite need antivenom?
No. Many bites cause only local effects and are managed with observation, while antivenom is reserved for bites causing significant envenoming, as decided by the medical team.
Why can it cause allergic reactions?
It is made from animal blood, so the body can react to it as a foreign substance, which is why it is given in hospital with emergency treatment to hand.
What should I do if bitten by an adder?
Keep the bitten limb still and low, remove rings and tight items, and get to hospital, as effects can develop over hours and may need treatment.
How is it given?
It is given in hospital, usually as an infusion into a vein, with the team watching closely for any allergic reaction.
Authoritative sources
- BNF
- NICE CKS
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