any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure

relating to epinephrine (its release or action)

a powerful vasoconstrictor used to dilate the pupils and relieve nasal congestion

an adrenergic drug used in many preparations to relieve allergic reactions or respiratory infections