Is Epinephrine still the power house drug it used to be?

By Geoff Murphy

By Geoff Murphy

Is Epinephrine still the power house drug it used to be?

Epinephrine has been plugged into at least half a dozen different treatment protocols. While traditionally it is used for the first line treatment of anaphylaxis, it is used for bronchospasm, all types of cardiac arrest, and as a vasopressor in shock patients. Question is, is it really that effective?? 
Epinephrine is Anaphylaxis
It is hard to argue epinephrine works in anaphylaxis. During an anaphylactic reaction the body releases large amounts of histamine. This histamine causes severe swelling, bronco constriction, and hypotension due to distributive shock. Epinephrine stops histamine release which limits swelling, it is a bronchodilator, and it is a vasoconstrictor. It's not very often one drug can be this effective, it certainly has its place in anaphylaxis.
Epinephrine is Bronchospasm
Epinephrine is not typically used as first line treatment, however because of its powerful bronchodilator properties it is used in severe cases. It has shown to be effective in severe cases of bronchospasm.
Epinephrine in Cardiac Arrest
Here is where the medical community has its doubts. In theory, epinephrine is used as a vasoconstrictor during cardiac arrest which in turn allows CPR to perfuse the brain with less work. However recently the American heart association studies have shown there is no increase in return of spontaneous circulation with the use of epinephrine, no increased chance of survival, which in turn means no increase in patients walking out of hospital. There is a good chance epinephrine will have  the same fate as atropine in cardiac arrest after no evidence shows success. 
Epinephrine As a Vasoconstrictor 
10 years ago this was a more common practice. Then the favour went to dopamine, and even now the more common vasopressor is norepinephrine. What makes epinephrine a less favourable choice is because of its beta1 properties. It significantly increases cardiac workload and oxygen consumption. With a patient in significant shock increasing the heart rate and cardiac work is not recommended.  
Epinephrine certainly still has its purpose with our anaphylaxis patients and bronchoconstriction patients. However evidence has shown it is not the powerhouse life saver it once was in cardiac arrest. Students will continue to study epinephrine for years to come. It is a powerful life saving drug, however it does have its limitation like any other drug. 
Stay safe out there!


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