WordNet (r) 3.0 (2006):

vasoconstrictive
    n 1: 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 [syn:
         vasoconstrictor, vasoconstrictive, pressor]