Epinephrine Pharmacology

The Effects of Epinephrine:

Epinephrine (Epi):

  • commonly known as adrenaline
  • a chemical that narrows blood vessels and opens airways in the lungs
  • can reverse severely low blood pressure
  • secreted mainly by the medulla of the adrenal glands
  • functions primarily to increase cardiac output and to raise blood glucose levels
  • normally released during acute stress
  • its effects prepare an individual for “fight or flight”, which is why it is a primary medication for non-perfusing cardiac arrests

Indications for Use of Epinephrine:

Epinephrine is used in symptomatic bradycardia and cardiac arrest arrhythmias such as:

Epinephrine would be administered after atropine as an alternative to dopamine.  It can also be administered to treat severe hypotension.

Additionally, epinephrine can be administered when external pacing and atropine fail and when bradycardia causes hypotension.  It can safely be administered with phosphodiesterase enzyme inhibitors.

Epinephrine is also an effective treatment for anaphylaxis.  Epinephrine should be combined with large volumes of fluid, corticosteroids, and antihistamines.

Epinephrine Precautions & Contraindications:

Caution should be used when administering epinephrine in cases where raising the blood pressure and increasing heart rates may cause myocardial ischemia, angina, and increased demand for myocardial oxygen.

High doses do not improve neurological outcomes or survival rates and may actually contribute to post-resuscitation complications like myocardial dysfunction.

Adult Dosage for Epinephrine:

Epinephrine is available in 1:10,000 or 1:1,000 concentrations.

To treat cardiac arrest:

  • Epinephrine should be delivered IV/IO at 1 mg (which is 10 mL of 1:10,000 solution)
  • Should be administered every 3 to 5 minutes during resuscitation
  • Each dose should be followed with 20 mL normal saline flush
  • Arm of delivery should be elevated for 10 to 20 seconds after dose delivery
  • If epinephrine delivery is administered via endotracheal tube, 2 to 2.5 mg of epinephrine should be diluted in 10 mL normal saline before administering
  • Higher dose epinephrine (up to .2 mg/kg) may be used for specific indications like beta blocker or calcium channel blocker overdose
  • If administering epinephrine as a continuous infusion, the initial rate should be .1 to .5 mcg/kg/min.

To treat profound bradycardia or hypotension, the following should be delivered:

  • 2 to 10 mcg per minute, titrated to patient’s response
  • A combination of 1 mg of epinephrine (1 mL of 1: 1,000 solution) to 250 mL or 500 mL of normal saline, via IV infusion drip

To treat anaphylactic shock, a medical professional should administer epinephrine 1:1,000 at .01 mg/kg, delivered via intramuscular delivery.