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Anaphylaxis is a life threatening allergic reaction that can occur within minutes of exposure to a trigger substance. The first line of treatment for an anaphylactic reaction is the injection of adrenaline using an epinephrine auto-injector such as an EpiPen or AnaPen.

How does adrenaline work with anaphylaxis?

EpiPen and AnaPen contain the active ingredient adrenaline, also referred to as epinephrine. Adrenaline is a hormone that is naturally produced by the adrenal glands in the body in times of stress. This prepares the body for extra energy exertion to allow the body to more readily handle life threatening situations.

When someone has an anaphylactic reaction they may encounter the following symptoms:

  • Tightness of the throat from swelling
  • Difficulty breathing
  • Tongue & facial swelling
  • Hoarse voice or difficulty speaking
  • A wheeze or persistent cough
  • Collapse or falling unconscious
  • Becoming pale or floppy (young children)
  • Abdominal pain & vomiting
  • Hives, welts & body redness

The adrenaline administered through an auto-injector works to reverse these symptoms by acting on alpha and beta adrenergic receptors in the body. The alpha receptors in your body are located on the walls of blood vessels. Adrenaline stops your blood pressure from falling too low by stimulating these receptors, causing the blood vessels to narrow. This also redirects blood to vital organs.

Other life threatening symptoms that adrenaline reverses include throat tightness, hives, itching and skin swelling. Adrenaline reduces throat tightness by acting on Beta receptors which are found in the heart and lungs. It opens and relaxes the airways by stimulating these receptors, making it easier to breathe. Adrenaline also stimulates beta receptors in the heart which make it beat stronger and faster.

Adrenaline should be administered to someone going into anaphylactic shock as soon as possible. An auto-injector is only used as emergency treatment. After experiencing anaphylactic symptoms you should also see a medical professional to receive further treatment.

How do I use an adrenaline auto-injector?

Adrenaline auto-injectors are prescribed to those who are believed to have anaphylaxis. These injections come pre-filled with a solution that automatically injects when pushed firmly against skin. An EpiPen or AnaPen auto-injector should be injected into the outer-mid thigh and should NOT be injected into veins, fingers, toes, hands or feet. You should inject someone as soon as you detect the first signs of a serious allergic reaction. If you have anaphylaxis you should follow the advice of your doctor when using an auto-injector and carefully read the instructions that come with it. Always have your auto-injector with you so that you can inject adrenaline quickly if you experience an allergic reaction.

For a diagram and step by step instructions on how to use and auto-injector please see the Australasian Society of Clinical Immunology and Allergy Action Plan for Anaphylaxis.

First Aid for Anaphylaxis

If someone’s symptoms and signs suggest anaphylaxis you should follow their Anaphylaxis Action Plan or take the following steps:

  • Lay victim flat, do not stand or walk, if breathing is difficult, allow to sit
  • Prevent further exposure to the triggering agent if possible
  • Administer adrenaline through auto-injector:
    • Child less than 5 years – 0.15 mg intramuscular injection.
    • Older than 5 years – 0.3mg intramuscular injection
  • Call an ambulance
  • Administer oxygen and / or asthma medication for respiratory symptoms.
  • Further adrenaline should be given if no response after five minutes.
  • If breathing stops follow resuscitation and life support procedures.

Key things to remember

  • If you have an auto-injector ask your doctor to demonstrate how to use it
  • Be aware of expiration date on your auto-injector and replace when necessary
  • Administer adrenaline at the first signs of an anaphylactic reaction
  • Seek emergency medical treatment immediately after adrenaline is injected
  • Most auto-injectors contain enough solution for one injection
  • If you receive an accidental injection of adrenaline seek medical help

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This post was written by awfa

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