Epinephrine is a sympathomimetic adrenergic agonist with non-selective activity on all adrenergic receptors and dose-dependent affinity.

At low doses (<10 mcg/min), it has the strongest affinity for β₁ receptors and minimal for ⍺₁, making it an excellent inotrope and chronotrope for treating cardiogenic shock without increasing peripheral resistance.

At high doses (10 – 30 mcg/min), it becomes a broad-spectrum vasopressor, owed to an increase in ⍺₁-mediated vasoconstriction with preserved positive impact on cardiac function.

Activity on β₂ receptors causes bronchodilation, making Epinephrine the treatment of choice for anaphylaxis or status asthmaticus.

With such versatile effects and countless clinical applications, it is not surprising that Epinephrine is one of the most widely used medications.