About Adrenaline

This page details how adrenaline works, what auto-injectors are available, who should be prescribed adrenaline, how many auto-injectors should be carried, when to use adrenaline and other important information.

If you are prescribed adrenaline, it should be available at all times – with no exceptions. After an injection is given, someone should call the emergency services immediately as the person must be observed in case there is a secondary reaction (known as biphasic anaphylaxis) and further treatment may be needed. If you are at risk of serious allergic reactions, you may want to purchase and wear a medical alert bracelet or pendant.

We offer general information only and you should always be guided by your GP or allergy specialist.

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living happily with anaphylaxis serious allergies

What is Anaphylaxis?

Anaphylaxis (also known as an anaphylactic reaction) is a serious allergic reaction that is rapid in onset and on rare occasions causes death. There may often be a rash or swelling affecting the skin and sometimes vomiting and diarrhoea. However, the more serious and severe features of the reaction are caused by swelling and tightening of the airways causing difficulty in breathing and/or a sudden fall in the blood pressure leading to dizziness and even collapse.

How Adrenaline Works

Adrenaline acts quickly to open up the airways, reduce their swelling and raise blood pressure. To work effectively, it must be given as soon as possible if there are any signs of a serious allergic reaction. With early treatment, those more serious symptoms are easier to reverse.

adrenaline for allergies advice

Who Should Be Prescribed Adrenaline?

In the past, this question has caused some disagreement among medical experts. Most would agree that adrenaline should be prescribed for those at risk of anaphylaxis. However, carrying adrenaline long-term may not be required if the trigger can be easily avoided, for example, in the case of oral prescription drugs and injection-administered drugs, unless there are additional risk factors.

Prescribing Adrenaline

Identifying people who have never had a severe allergic reaction, but are at risk of anaphylaxis, can be difficult and requires the experience of an allergy specialist. GPs should refer their patient to an allergy clinic for assessment.

The most recent specialist advice in the UK comes from the 2016 guideline of the British Society for Allergy and Clinical Immunology (BSACI), ‘Prescribing an adrenaline auto-injector’. The decision to prescribe adrenaline should be part of an approach that includes a thorough assessment of the patient. This can best be done at a specialist allergy clinic or by a GP who has had specialist training in allergy management

People who should be considered for long-term provision of an adrenaline auto-injector include those:
  • right_arrow_orange_icon Who have suffered an anaphylactic reaction where the cause is unknown (known as idiopathic anaphylaxis).
  • right_arrow_orange_icon Who have suffered an anaphylactic reaction where the known allergic trigger cannot easily be avoided.
  • right_arrow_orange_icon Who are allergic to high-risk allergic triggers, for example peanuts and nuts, with other risk factors also present, such as asthma, even if the reaction was relatively mild.
  • right_arrow_orange_icon Who had a reaction in response to trace amounts of the allergic trigger.
  • right_arrow_orange_icon Where an anaphylactic reaction triggered by food is only likely to occur if that food is eaten around the time of physical exercise (known as Food-Dependent Exercise-Induced Anaphylaxis or FDEIA).
  • right_arrow_orange_icon Where other significant risk factors are present (e.g. asthma in someone with food allergy).
  • right_arrow_orange_icon Where significant time is spent in a location without access to emergency medical care.

Adrenaline Auto-Injectors

The adrenaline three types of auto-injectors available in the UK. They are each designed for self-use and that is why they are usually referred to as ‘adrenaline auto-injectors’ or ‘AAIs’. You can find out more about each below.

Advice on Adrenaline Auto-Injectors

If you have been prescribed an adrenaline auto-injector, it is vital that you are shown how to use it. It is the responsibility of the medical professional who prescribed it to you to ensure that you are given training and check you understand the information provided. You are entitled to ask for training and follow-up training at a later date.

Adrenaline auto-injectors have a use-by date. If you carry them, you should make sure you ask your GP for a replacement before this date. The companies listed above run an expiry alert service. If you register your device and expiry date, they will send you a reminder when it is due to expire.


How is Adrenaline Administered?

The place where the adrenaline is administered is the same for the three brands of auto-injector.

EpiPen®, Jext® and Emerade® are injected into the middle of the outer thigh (upper leg), through clothing if necessary.

Training should be given to everyone who might be required to give you the adrenaline in an emergency, such as your family members, colleagues, school staff and day nursery staff.

You can find help on the website relevant to the adrenaline auto-injector you carry.

When Should Adrenaline be Administered?

You should administer your adrenaline auto-injector without delay if you believe your allergic reaction is serious or becoming serious. Call for an ambulance immediately or get someone else to call for you. They should state that the person is suffering from anaphylaxis (pronounced ana-fill-axis).


The following symptoms should help you recognise a potentially life-threatening reaction


swelling in the throat, tongue or upper airways (tightening of the throat, hoarse voice, difficulty swallowing)


sudden onset wheezing, breathing difficulty, noisy breathing


dizziness, feeling faint, sudden sleepiness, tiredness, confusion, pale clammy skin, loss of consciousness

Playing it safe

Steady deterioration is also a warning sign that may mean an injection of adrenaline is vital. Play safe and use your AAI, if you have any suspicion that a reaction is getting worse. Your allergy specialist should help you understand in advance what symptoms provide a signal that a severe reaction is occurring.

The BSACI recommends that a written Allergy Action Plan should be provided by your doctor or allergy specialist, which should be individually tailored for each patient and should include advice as to when the adrenaline auto-injector should be used and first aid measures such as positioning.

Positioning is important. You should lie down with your legs raised to help blood flow back to your heart and vital organs. If you are struggling to breathe, you may need to be propped up, but this should be for as short a time as possible. You must avoid any sudden change in posture. You must not stand up, or sit in a chair, even if you are feeling better. This could lower your blood pressure drastically causing your heart to stop.


Department of Health’s 2017 guidance document

Our Frequently Asked Questions in Schools factsheet

AAIs in schools 

Watch our videos


Dr Michel Erlewyn-Lajeunesse and Anaphylaxis UK's Simon Williams talk about adrenaline

Simon Williams and Dr Michel Erlewyn-Lajeunesse, Consultant in Paediatric Allergy at Southampton Hospital talk about adrenaline.

  • • How does adrenaline work?
  • • When should someone take adrenaline when having an allergic reaction?

How to use adrenaline auto-injectors with Dr Matt Doyle

Anaphylaxis can come on very quickly. As soon as you suspect anaphylaxis you must use one of your adrenaline auto-injectors (AAI) without delay. Don’t wait to see how bad it is, or whether it will get worse. If in doubt, use your AAI. Simon talks to Dr Matt Doyle about how to use the three different types of AAI, when to use them and what to do in an emergency.

educating schools about adrenaline for allergies

The 2017 Legislation Covering Adrenaline in Schools

Legislation which came into effect in 2017 enables schools in the UK to buy AAIs without a prescription for emergency use on children who are at risk of anaphylaxis but whose own device is not available or not working.

The injection can be given to a child where both medical authorisation and written parental consent for use of the spare AAI has been provided.

Adrenaline FAQs

  • How many injectors should I carry?

    You should be prescribed two AAIs. See NICE guidelines (updated in August 2020) and EMA recommendation (June 2015)

  • Does adrenaline carry any risk?

    Some people worry that adrenaline may be harmful, but evidence supports the relative safety of prescribed adrenaline devices so long as they are used correctly. Taking this evidence into account, we advocate that if you are unsure whether an allergic reaction is severe enough to require adrenaline, then it should be administered.

  • Does adrenaline have any important drug interactions?

    Anaphylaxis may be made worse by beta-blockers (used to control heart rhythm, treat angina, and reduce high blood pressure) as these drugs decrease the effectiveness of adrenaline. Other drugs may also be contra-indicated. This is a matter for discussion with your GP or allergy specialist.

  • How do I store adrenaline auto-injectors?

    EpiPen®, Jext® and Emerade® come with the following instructions on storage of the device: keep AAIs in their original containers to prevent light exposure, do not store above 25°C and do not freeze. For EpiPen® devices there is an additional instruction to not refrigerate the device. Adrenaline auto-injectors should be regularly checked to ensure the liquid is clear and colourless. If at any time the solution appears discoloured or contains particles the device should be replaced.

Key Messages

  • Adrenaline is the first line treatment for anaphylaxis, but it will only be effective if it is available at all times, is used correctly and is used promptly. If you have been prescribed adrenaline auto-injectors, you should have them with you everywhere you go. Your doctor who prescribed your adrenaline auto-injectors should show you how to use them or arrange for training for you and your family. Follow-up training at various intervals is also important. Trainer auto-injectors without a needle or drug can be ordered from the websites of the UK distributors (see above).
  • A call for an ambulance must always be made immediately after the adrenaline auto-injector is used, specifying that adrenaline has been given due to anaphylaxis (anna-fill-axis). If your condition deteriorates after making the initial 999 call, a second call to the emergency services should be made to ensure that an ambulance has been dispatched. A second dose of adrenaline can be given 5 minutes after the first dose if needed.
  • Positioning is important. You should lie down with your legs raised to help blood flow back to your heart and vital organs. If you are struggling to breathe, you may need to be propped up, but this should be for as short a time as possible. You must avoid any sudden change in posture. You must not stand up, or sit in a chair, even if you are feeling better. This could lower your blood pressure drastically causing your heart to stop.

Download our Adrenaline Factsheet

Download Now