NCIt definition : A direct-acting sympathomimetic amine chemically related to adrenaline and ephedrine
with potent vasoconstrictor property. Phenylephrine is a post-synaptic alpha-adrenergic
receptor agonist that causes vasoconstriction, increases systolic/diastolic pressures,
reflex bradycardia, and stroke output.;
Alternative definition : ACC/AHA: Phenylephrine is a sympathomimetic drug whose primary activity results from
stimulation of the alpha receptors of the vasculature, resulting in vasoconstriction
while producing comparatively mild direct cardiac effects.;