Indications for prescribing an adrenaline auto-injector device

• commonly available adrenaline preparations include:
  • adrenaline pre-loaded syringes
    • Min-I-Jet
  • adrenaline auto-injectors are authorised for the emergency treatment of severe acute allergic reactions (anaphylaxis) triggered by allergens in foods, medicines, insect stings or bites, and other allergens, as well as for exercise-induced or idiopathic anaphylaxis. Adrenaline auto-injectors available in the UK are (2):
    • Emerade
    • EpiPen
    • Jext
      
      
    • in addition to advice in the Summary of Product Characteristics and Patient Information Leaflet, each brand of adrenaline auto-injector has educational materials available for healthcare professionals and patients. People with allergies and their carers can also use manufacturers’ websites to order trainer devices and to sign up for expiry alert services.
    • each brand of adrenaline auto-injector is available in more than one strength (corresponding to the dose delivered by the device). Broadly, the lower strength is suitable for younger children and the higher strengths suitable for older children and adults.
    • only one brand of adrenaline auto-injector (Emerade) is available in a 500 microgram strength, with the other 2 brands being available in a maximum strength of 300 microgram. The labelled strength of adrenaline auto-injectors reflects the dose of adrenaline dispensed by the device in a single injection. However, the amount of adrenaline reaching the bloodstream in a particular time window can differ according to patient-specific and device-specific factors
      • evidence found that in healthy people, adrenaline auto-injectors of the same strength but with shorter needles and potentially higher propulsive force (EpiPen and Jext 300 micrograms) delivered more of the adrenaline dose to the bloodstream in the first 30 minutes than did the Emerade 300 microgram auto-injector (2)
        • as such, the Epipen or Jext brands of 300 microgram adrenaline auto-injector are both suitable alternatives to the Emerade 500 microgram adrenaline auto-injector
          
          
    • Advice for healthcare professionals (2):
      • Emerade 300 microgram and 500 microgram adrenaline auto-injectors have been re-supplied to the market following the implementation of corrective actions to resolve the issue that caused some devices to fail to activate and deliver adrenaline
      • for each adrenaline auto-injector, follow advice in the Summary of Product Characteristics to prescribe appropriate doses for individual patients (see section on dosing considerations)
      • remind patients to follow existing advice to carry 2 in-date adrenaline auto-injectors with them at all times and to replace them before they expire
      • provide patients and their caregivers with training and advice specific to their prescribed adrenaline auto-injector; encourage them to order a trainer device from the manufacturer to ensure they are familiar with using their auto-injector
      • suspected adverse drug reactions or defective medicines should be reported to the Yellow Card scheme
        
        
• Following emergency treatment for suspected anaphylaxis (3,4):
  • Follow the National Institute for Health and Care Excellence (NICE) guideline for the assessment and referral of patients suspected to have had anaphylaxis. Specifically:
    • all patients should be referred to a specialist clinic for allergy assessment
    • offer patients (or, if appropriate, their parent and/or carer) an appropriate adrenaline injector as an interim measure before the specialist allergy assessment (unless the reaction was drug-induced)
      • prescription of adrenaline auto-injectors is appropriate for all patients who have had anaphylaxis, with the exception of those with a drug-induced reaction (unless it is difficult to avoid future exposure to the trigger drug) (3)
    • patients prescribed adrenaline auto-injectors (and/or their parents/carers) must receive training in their use, and have an emergency management or action plan
      
      
  • following advice from MHRA, NICE guidelines currently recommend that patients prescribed adrenaline auto-injectors should have two devices available at all times. Patients (and those close to them, such as immediate family members, friends, carers) should receive training in their use, and practise regularly using a suitable training device so that they will know what to do in an emergency (4)

Adrenaline auto-injector devices (4)

• auto-injectors are often prescribed to patients at risk of anaphylaxis for early self-administration or injection by a carer or family member in the event of an anaphylactic reaction. Depending on the brand, they are available in three doses of adrenaline:
  • 150 micrograms (0.15 mg),
  • 300 micrograms (0.3 mg) and
  • 500 micrograms (0.5 mg)
  • healthcare professionals should be familiar with their use

Doses of emergency drugs for anaphylaxis and angio-oedema (3,4):

* IM: intramuscular

Notes:

• the majority of anaphylaxis episodes occurring in a community setting will respond to initial treatment with IM adrenaline, although currently around 10% receive more than one dose (3)
  • this may sometimes be due to the use of auto-injectors which cannot deliver an age/weight-appropriate dose in most patients
  • less than 1% of reactions are refractory to initial adrenaline treatment, and intensive care admissions for anaphylaxis are uncommon

Reference:

• Andrew P C McLean-Tooke, et al.Adrenaline in the treatment of anaphylaxis: what is the evidence? BMJ 2003; 327: 1332 - 1335
• MHRA. Drug Safety Update volume 15, issue 4: November 2021: 2.
• CKS (2021). Angio-oedema and anaphylaxis.
• Emergency treatment of anaphylactic reactions. Guidelines for healthcare providers. Working Group of the Resuscitation Council (UK).2021
• NICE. Anaphylaxis Guideline. www.nice.org.uk/guidance/CG134.