What Does Adrenaline Do?

AnaphylaxisAdrenaline is a  hormone that occurs naturally in the body. 
But how does this help us manage anaphylactic shock?

A sudden surge of adrenaline in the system works to make the heart beat stronger and faster. But did you know that it also has an effect on the smooth muscles of the airway and the gut? By relaxing these muscles the airway can open up nicely to improve oxygen flow. And anything currently passing through the gut will suddenly slow right down. Which is pretty handy if you need to run away from danger.

In effect, this natural response serves to prepare the body to either run away or fight back! We use a synthetic version of adrenaline called epinephrine to mimic this natural fight or flight response.

How Does Adrenaline help?

In anaphylactic patients, life threatening symptoms can include swelling of the airways and a sudden drop in blood pressure. By artificially activating the bodies fight or flight mechanisms we reverse the symptoms associated with life-threatening anaphylaxis.

Epinephrine works by:

  1. Improving the pumping effect of the heart
  2. Opening up the airway to allow for optimal air entry  AND
  3. Relaxing gastrointestinal movement

    Epinephrine is a synthetic version of Adrenaline,
    which is where the word “Epi-Pen” comes from…

Improving the pump

Anaphylaxis is life- threatening for several reasons, one being the rapid and dangerous decrease in blood pressure. If blood pressure drops, our vital organs don’t receive enough oxygen to work efficiently. As this progressively worsens, it has the potential to lead to complete systemic organ failure and subsequently death.

We administer adrenaline to encourage blood vessels to narrow and promote the hearts muscles to contract… together this works to improve blood pressure. (Which is the same reason medical professionals use it to manage cardiac arrest). By making the heart beat harder and faster, blood flow improves. Now, we can deliver sufficient oxygen to vital organs and tissues and assist in the removal of waste products.

Opening up the airway

Swelling of the lips, face and tongue can drastically reduce the ability to breath (obviously!). So if you notice symptoms including a hoarse/ raspy voice, wheezing or a persistent cough this could indicate inadequate airflow. Adrenaline (epinephrine) is used to help reverse these signs of bronchoconstriction. By allowing the smooth muscles in the airway to relax,  this helps to improve airflow and ultimately the patients’ ability to breathe.

Relaxing the Gastrointestinal system

As we mentioned earlier, adrenaline mimics the fight or flight response. If you were about to run away from danger it would be a very inconvenient time to stop for a bathroom break. So, in addition to improving blood and airflow, adrenaline (epinephrine) also works to relax the muscles in the stomach, intestines and bladder and slows down digestive processes.


For a how to guide and access to a quick tutorial video head on over to our blog titled “How to use an EpiPen” for more information.

Or better still, come and practice with one of our trainer EpiPen’s in one of our public First Aid Courses at our Wanneroo Training Venue. 
I promise there are no actual needles! 

Alicia White
Alicia White

Registered Paramedic - Perth, W.A.