Epinephrine is a potent, nonselective adrenergic agonist acting on alpha-1, alpha-2, beta-1, and beta-2 receptors. This high-yield 80/20 summary covers the essential clinical and exam concepts:

1. Expected Pharmacological Action & Mechanism

• Alpha-1 activation causes arteriolar vasoconstriction.
• Beta-1 activation induces positive inotropic and chronotropic responses, increasing cardiac workload and coronary vasodilation.
• Beta-2 activation drives bronchodilation, skeletal muscle vasodilation, and hepatic glycogenolysis.
• Alpha-2 activation inhibits insulin release and provides negative feedback on norepinephrine.
• Actions are mediated by cyclic AMP (increased by beta, decreased by alpha).