Epinephrine (also called adrenaline) is a hormone and medication your body naturally makes, and it’s also used as a life‑saving drug in emergencies.

What epinephrine is

  • Chemically, epinephrine is a catecholamine hormone and neurotransmitter produced mainly by the adrenal glands , the small organs on top of the kidneys.
  • It’s a key player in your “fight‑or‑flight” response , released when the body senses stress, danger, or intense emotion, ramping up heart rate, breathing, and energy availability.

What it does in the body

  • In a stress response, epinephrine:
    • Speeds up the heart and increases blood pressure to push more oxygen to muscles.
* **Opens airways** (bronchi) so breathing becomes easier.

* **Raises blood sugar** by stimulating the liver to release glucose, giving cells a quick energy boost.
  • As a neurotransmitter, it also helps regulate attention, alertness, and mood , and imbalances have been linked with anxiety, sleep problems, and some stress‑related conditions.

Epinephrine as a medication

Clinically, epinephrine is used as a drug to counter life‑threatening situations:

  • Anaphylaxis (severe allergic reaction) – Epinephrine is the first‑line, life‑saving treatment for anaphylaxis caused by foods, insect stings, drugs, or other allergens.
* It works by:
  * Opening constricted airways
  * Raising blood pressure
  * Reducing swelling and hives
  • Cardiac arrest and shock – Used in emergency settings to help restart or stabilize the heart rhythm and support blood pressure.
  • Asthma and airway emergencies – Sometimes given to relieve severe bronchospasm (tight airways) when other treatments aren’t enough.

In practice it’s often delivered as an auto‑injector (such as EpiPen) or as an injection in hospitals.

Quick‑glance comparison

Aspect| Natural epinephrine (hormone)| Medication epinephrine (drug)
---|---|---
Source| Made by adrenal glands in the body 15| Manufactured and injected or auto‑injected 26
Main role| Part of stress/fight‑or‑flight response 13| Emergency treatment of anaphylaxis, cardiac issues, severe asthma 279
Key effects| Faster heart rate, higher blood pressure, more alertness 15| Rapid reversal of airway swelling, shock, and low blood pressure 79

Safety and important notes

  • Epinephrine is powerful; when given as a drug it can cause rapid heartbeat, anxiety, headache, tremor, or high blood pressure , so it’s used under medical direction or in emergencies patients are trained for.
  • Because it’s the only drug that can reverse anaphylaxis , health organizations strongly recommend that people at risk carry an epinephrine auto‑injector and know how and when to use it.

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