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Everything You Need to Know About Epinephrine Auto-Injectors

Edited by Michelle Asselin

Up to 30% of Canadians live with severe allergies, making up 1% of all emergency department visits each year. The most common allergy triggers include peanuts, tree nuts, shellfish, fish, milk, eggs, wheat, insect stings or bites, and medications. However, one of the main challenges to treating allergies is that we often can’t anticipate how severe the reaction will be. The most extreme and life-threatening allergic reaction is called anaphylaxis, and its occurrence has been increasing over the years. Individuals who are at a higher risk of anaphylaxis include those who have a history of allergic reaction or anaphylaxis, asthma, eczema, seasonal allergies, cardiovascular disease, stress, and certain medications such as anti-inflammatories, antibiotics, and biologics. Given the high prevalence of allergic reactions, it is important to be prepared to respond in a timely manner.

Common Symptoms

Anaphylaxis often occurs within 5 to 30 minutes following allergen exposure and has the potential to be fatal if not addressed quickly. Anaphylaxis presents with symptoms involving the skin and mucosal membranes such as hives, rash, flushing, swollen lips, tongue, or throat. In addition to these symptoms, at least one of the following is also present:

  • Respiratory decline such as shortness of breath, wheezing, or stridor (a high-pitched sound while inhaling or exhaling)

  • Symptoms of low blood pressure or end-organ dysfunction such as feeling faint, loss of consciousness, or persistent urge to urinate

  • Severe gastrointestinal symptoms such as nausea, vomiting, or abdominal pain

In cases where low blood pressure, difficulty breathing, or throat swelling is present, anaphylaxis must be suspected regardless of the presence of skin involvement. The severity of previous anaphylactic attacks is not predictive of future anaphylaxis severity. As such, it’s very important we remain prepared to address the unpredictable nature of anaphylactic reactions.

What is an Epinephrine Auto-Injector?

A device called an epinephrine auto-injector (EAI) is used when an anaphylactic reaction is suspected. They can be obtained via prescription or can be purchased over-the-counter at any pharmacy. EAIs are pre-filled automatic injection devices that administer a set dose of epinephrine. Epinephrine works by relaxing the muscles of the airways to ease breathing. It also increases blood pressure and relaxes the muscles in the stomach, intestines, and bladder. Common side effects one can expect include anxiety, shakiness, sweating, nausea, headache, dizziness, or a rapid heart rate. These symptoms usually go away within 30 minutes of injection and should NOT deter someone from administering an EAI during an anaphylactic episode.

Dosing Guidelines

The dose of epinephrine that is administered through an EAI is based on a person’s weight. The EAIs currently available in Canada are EpiPen, Allerject, and Emerade. There are slight differences between the products (e.g., needle length, administration technique), however they are all very effective at treating anaphylaxis.

How to Use


Remember: Blue to the sky, Orange to the thigh!

  1. Remove the EpiPen from the clear carrier tube.

  2. Grasp the EpiPen with the orange tip pointing downward and remove the blue safety cap by pulling straight up.

  3. Place the orange tip against the middle of the outer thigh at a right angle.

  4. Swing and push the auto-injector firmly into the thigh until it “clicks”. You may inject through clothing.

  5. Hold firmly in place for 3 seconds – count slowly.

  6. Remove the EpiPen from the thigh and gently massage the injection site. After removal, the orange needle cover will be extended and locked in place.

  7. Call 911 and seek immediate medical care.


Note: Allerject comes with English or French voice-assistance that guides users through the steps to administer the auto-injector.

  1. Pull Allerject from the outer case by pulling straight up.

  2. Pull off the red safety guard located at the base of the auto-injector. The safety guard is meant to be tight, so pull firmly.

  3. Place the black end against the middle of the outer thigh and press firmly until you hear a “click and hiss” sound. You may inject through clothing.

  4. Hold firmly in place for 5 seconds – count slowly.

  5. Remove Allerject from the thigh and gently massage the injection site. After removal, the black case will lock into place. The voice instructions will say “Allerject has been used” and the lights will blink red.

  6. Call 911 and seek immediate medical care.


  1. Remove the needle cap.

  2. Press the tip against the middle of the outer thigh at a right angle until it “clicks”. You may inject through clothing.

  3. Hold in place for 3 seconds – count slowly.

  4. Remove Emerade from the thigh and gently massage the injection site. After removal, the plunger will be visible.

  5. Call 911 and seek immediate medical care.

Additional Notes to Consider

If the symptoms are not improving or are getting worse after your first injection, you may inject another dose after 5 to 15 minutes. However, do not use more than 2 doses. It is important that during this time, the patient is able to receive emergency medical services. Seeking immediate medical care is essential because epinephrine does not cure the allergic reaction, it simply buys the patient enough time to get to a hospital where they can receive proper treatment and monitoring.

Following appropriate medical care, make sure to pick up another two EAIs from the pharmacy. EAIs should be kept at room temperature and away from direct sunlight. The EAI should be replaced before it expires, if it becomes discoloured, contains solid particles, or if there are any signs of leakage.

Key Takeaways

The symptoms of anaphylaxis vary and may not be obvious in all cases. Whenever in doubt, it is always better to give the injection. In life-threatening allergic situations, giving epinephrine will always do more benefit than harm. An epinephrine injection does not replace the need for further medical care, so it is imperative to call 911 after epinephrine has been administered. Individuals with anaphylactic allergies (and their friends and family) must be confident in knowing when and how to use EAIs in the case of an emergency. Pharmacists are a highly accessible healthcare resource and are there to help everyone understand how EAIs are used to treat anaphylaxis. If you have any questions, don’t be afraid to talk to your pharmacist!

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  1. Cardona V, Ansotegui IJ, Ebisawa M, et al. World Allergy Organization Anaphylaxis Guidance 2020. WAOjournal. 2020;13(10):100472. doi:

  2. Emerade (Systemic). In: Lexi-Drugs. Lexi-Comp, Inc. Updated June 25, 2021. Accessed June 25, 2021.

  3. Hospital Emergency Visits for Anaphylaxis Double in Canada. Allergic Living. September 17, 2015. Accessed October 12, 2021.

  4. Kaleo. Allerject. In: Compendium of Pharmaceuticals and Specialities. Canadian Pharmacists Association. Updated November 21, 2019. Accessed June 25, 2021.

  5. Pawankar R, et al. Introduction and executive summary: Allergic disease as a global public health issue. In: Pawankar R, et al., eds. World Allergy Organization (WAO) White Book on Allergy. World Allergy Organization; 2011. Accessed October 12, 2021.

  6. Pfizer. EpiPen. In: Compendium of Pharmaceuticals and Specialities. Canadian Pharmacists Association. Updated May 30, 2017. Accessed June 25, 2021.

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