Epinephrine The active sympathomimetic hormone from the adrenal medulla in most species. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. It is used in asthma and cardiac failure and to delay absorption of local anesthetics.
[1. A catecholamine that is the chief neurohormone of the adrenal medulla of most species; also secreted by certain neurons. The l-isomer is the most potent stimulant (sympathomimetic) of adrenergic α- and β-receptors, resulting in increased heart rate and force of contraction, vasoconstriction or vasodilation, relaxation of bronchiolar and intestinal smooth muscle, glycogenolysis, lipolysis, and other metabolic effects; used in the treatment of bronchial asthma, acute allergic disorders, open-angle glaucoma, cardiac arrest, and heart block, and as a topical and local vasoconstrictor. Generally used salts are epinephrine hydrochloride and epinephrine bitartrate, the latter most frequently used in topical preparations.