Source:http://linkedlifedata.com/resource/umls/id/C0304428
NCI: The bitartrate salt form of phenylephrine, a direct-acting sympathomimetic amine chemically related to adrenaline and ephedrine with potent vasoconstricting activity. Phenylephrine is a post-synaptic alpha-adrenergic receptor agonist that causes vasoconstriction, increases systolic/diastolic pressures, reflex bradycardia, and increases stroke output.