Vasopressin, also known as antidiuretic hormone (ADH), is a peptide hormone made in the hypothalamus and has both an immediate and long term effect on hemodynamics. The immediate effect is as a direct peripheral vasoconstrictor. A slower acting mechanism is the process of increasing collecting duct permeability and retaining water. Possibly increasing intravascular volume, certainly increasing total body water.
Epinephrine has many rapid onset cardiovascular effects including alpha mediated vasoconstriction, beta mediated increase in heart rate, lusitropy, and inotropy. At doses used in ACLS (~ 1 mg), epinephrine and vasopressin behave similarly