ELI5: why do we inject adrenaline (Epi Pen) into someone having an allergic reaction?

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What’s the mechanism behind an adrenaline injection, eg. Epi Pen, saving someone with a serious allergic reaction?

Comments

  1. DisplayGood8862 Avatar

    Epinephrine causes a “fight or flight” response which dilates the airways to allow more efficient breathing in case you need to run or fight. Some allergic reactions can cause people’s airways to swell closed, epinephrine will often counteract this response, at least long enough to get to a hospital.

  2. charge2way Avatar

    The main thing it does for an allergic reaction is to open up the airways. This can offset the swelling from the reaction that’s causing the airways to become closed in the first place. It does this by activating your bodies sympathetic nervous system and turning on “fight or flight” mode. Since this mode relies on getting lots of oxygen into your lungs to fuel either fight or flight, it also opens up your airways.

    *This is a gross simplification and probably outright wrong in some places, but it’s a good enough mental model for an ELI5.

  3. Pocok5 Avatar

    Dumping adrenaline in blood activates a lot of emergency functions for getting out of danger. One of these is turning off swelling and such immune responses. There will be time to screw about with that foreign dust on your tongue after you run away from that lion!

  4. Raven_1090 Avatar

    When you eat something hot/spicey, you try to mitigate the burning by eating the opposite of that, that is something cold like drinking water. Same principle with epinephrine. The allergen produces an allergic reaction in the body, which leads to vasoconstriction, narrowing of your breathing pathways. Epinephrine causes dilation. Hence providing relief.