Epinephrine, how awesome is this drug?!

Epinephrine (Epi, Adrenaline) is the most common drug in resuscitation. Epi is given to almost every patient in a cardiac arrest. There is no total dosage limit to Epi. It’s used by non-healthcare workers in Epi-Pens, used by John Travolta in Pulp Fiction and by almost every medical worker who has worked a cardiac arrest. But what does it really do? Does Epi give us a heart beat back? Does Epi decrease the defibrillation threshold? Is the word Adrenalin really a trademark?! Here’s your chance to find out!


Trade names: EpiPen, Twinjet, Adrenalin (yes, it’s a trade name owned by Pfizer)
Drug class: Alpha-adrenergic agonist, Beta-adrenergic agonist (Makes everything speeds up)
Pregnancy class: C (There are risks to fetus shown in animals, but the benefits to the mother out weigh the risks to the fetus)

Before we go into what Epi does, there is one more side note to know. Epinephrine comes in two concentrations. 1:10,000 and 1:1,000. 1:10,000 means 1mg in 10 ML. 1:1,000 means 1mg in 1 ML. 1:10,000 goes via IV or IO and generally comes packaged in a preloaded syringe. 1:1,000 comes in a vial or ampule and goes via IM or ETT (endotracheal tube). Oh, and everything we’re talking about (dosages and such) are all for an adult and based off the 2010 AHA Guidelines.

 Epinephrine Prefill A 10ML pre-filled Epinephrine syringe

Epinephrine Ampule A 1ML Epinephrine ampule

So now that we know what Epi is, we can talk about what it does.

Cardiac arrest: During cardiac arrest, 1mg of is given every 3-5 minutes, preferably via IV/IO. But why? That’s the million dollar question. I was always told “because Epi get’s us a heart beat back”. I knew when I was told this, in paramedic school, that it wasn’t true. I’m sure you know it’s not true either. Here’s what Epi does:

  • Science Jargon: Epinephrine increases peripheral resistance from the α1receptor & increases cardiac output via the β1 receptor. The goal of this is to reduce all of the peripheral circulation and increase the cerebral and coronary perfusion pressures. This will then cause an increase of Oxygen exchange in the bodies cells.
  • Non-scientific words: Epinephrine will constrict all of the victims peripheral vasculature. This will allow more blood to go to the coronary arteries and to the brain during CPR, increasing the chances of a ROSC (return of spontaneous circulation).

Anaphylaxis: Anaphylaxis is a life threatening emergency in which inflammatory mediators are released from basephils and mast cells. This inflammatory response causes the release of histamine. Histamine causes the bronchial muscles to constrict, vasodilation and fluid leakage from the blood vessels.

  • Science Jargon: IV administration of epinephrine causes vasoconstriction via the αadrenoceptor. Due to the various effects α1 and β2 receptors, the blood pressure may be elevated or lowered.
  • Non-scientific words: Epi helps the body calm down. The victims blood vessels will constrict, dropping their blood pressure, causes the swelling to go down, and relaxes the airway, allowing the patient to breath.

This is only a brief look into Epinephrine. Epi is an extremely useful drug in emergency medicine. For more detailed information on Epinephrine, be sure to check out the National Library of Medicine.