The Cardiac vascular system

If you were to design a medication for high blood pressure, how would you design it? What system(s) would you target? How would this drug work on a biochemical level (what physiological pathways would it affect)? Could it have multiple targets? What would be the potential side effects? (Be creative – this drug could target somewhere other than the Cardiac vascular system. Also, do not just list drugs that already exist by name.)