Article date: May 2014
Anaphylaxis is a life-threatening systemic allergic reaction. It can be triggered by a broad range of allergens. The most common allergens are certain foods, drugs, and venom (including wasp and bee stings).
An intramuscular injection of adrenaline in the outer thigh is the treatment of choice for someone having an anaphylactic reaction.1 Because the onset of anaphylaxis can be very fast, the individual should use an adrenaline auto-injector at the first signs of a severe reaction, then call for emergency medical help. Signs of a severe reaction include:
- swelling in the throat (altered voice, difficulty swallowing or breathing)
- dizziness, feeling faint, tiredness (symptoms of low blood pressure)
If in doubt about severity, or if previous reactions have been severe, the individual should use an adrenaline auto-injector. If the individual does not feel better after the first injection, the second auto-injector should be used 5 to 15 minutes after the first.
Adrenaline auto-injectors currently licensed for use in the UK are Emerade, EpiPen, and Jext. Each is available in a 150 microgram and 300 microgram dose. Emerade is also available in a 500 microgram dose.
The MHRA has recently conducted a review of all adrenaline auto-injectors approved in the UK. Strengthened warnings, have been included in the product information as a result.
Advice for healthcare professionals:
- Ensure that people with allergies and their carers have been trained to use the particular auto-injector that they have been prescribed. Injection technique varies between injectors.
- Encourage people with allergies and their carers to obtain and practise using a trainer device (available for free from the manufacturers’ websites).
Advice to give to people with allergies and their carers:
- Carry two adrenaline auto-injectors at all times. This is particularly important for people who also have allergic asthma as they are at increased risk of a severe anaphylactic reaction.
- Use the adrenaline auto-injector at the first signs of a severe allergic reaction.
Take the following actions immediately after every use of an adrenaline auto-injector:
- Call 999, ask for an ambulance and state “anaphylaxis”, even if symptoms are improving.
- Lie flat with the legs raised in order to maintain blood flow. If you have breathing difficulties sit up to make breathing easier.
- Seek help immediately after using the auto-injector and if at all possible stay with the person while waiting for the ambulance.
- If the person does not start to feel better, the second auto-injector should be used 5 to 15 minutes after the first
- Check the expiry date of the adrenaline auto-injectors and obtain replacements before they expire. Expired injectors will be less effective.
Article citation: Drug Safety Update volume 7 issue 10, May 2014: A3.