Adrenaline pre-loaded syringes - indications for prescribing if history of allergic reactions

Min-I-Jet Adrenaline is available as pre-loaded syringes in s.c.(G25 needle) and i.m.(G21 needle) forms each containing 1mg in 1ml (1:1000).

Adrenaline is also available in the form of auto-injectors (1,2)

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:

• 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

Further information for prescribers and patients on adrenaline blood level data is included in the MHRA summary (2) and in the Summary of Product Characteristics for each medicine

Epipen is a automatically self-injecting device containing 1:1000 adrednaline solution giving 0.3mg in 0.3ml (adult version) or 0.15mg (junior version).

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

* IM: intramuscular

Advice for healthcare professionals to provide to patients and carers (5):

• adrenaline auto-injectors (AAIs) should be used without delay if anaphylaxis is suspected, even if in doubt about the severity of the event
• signs may include swelling in the throat or tongue, wheezing or breathing difficulty, dizziness, tiredness and confusion
• immediately dial 999 to summon emergency medical help after administering adrenaline; say anaphylaxis ("ana-fill-axis")
• if you are not already lying down, lie down flat and raise your legs (if you're pregnant, lie on your left side); this will assist blood flow to the heart and vital organs
• stay lying down even if you feel better
• if you struggle to breathe, you can gently sit up - don't change position suddenly; you should then lie down again as soon as you can
• do not stand up even if someone encourages you to
• use your second AAI if you haven't improved after 5 minutes
• you should always carry 2 AAIs at all times; check the expiry dates and see a pharmacist if you need a replacement
• report any suspected defective AAIs to the Yellow Card scheme.

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:

• (1) Andrew P C McLean-Tooke, et al.Adrenaline in the treatment of anaphylaxis: what is the evidence? BMJ 2003; 327: 1332 -1335
• (2) MHRA. Drug Safety Update volume 15, issue 4: November 2021: 2.
• (3) CKS (2021). Angio-oedema and anaphylaxis.
• (4) Emergency treatment of anaphylactic reactions. Guidelines for healthcare providers. Working Group of the Resuscitation Council (UK).2021
• (5) MHRA. Drug Safety Update volume 16;issue 11:June 2023:3