Angiotensin II receptor blockers (ARBs). These help relax blood vessels by blocking the action, not the formation, of angiotensin, a chemical in your body that narrows blood vessels. ARBs include valsartan (Diovan), losartan (Cozaar) and others.
Calcium channel blockers. These medications prevent calcium from entering heart and blood vessel muscle cells, thus causing the cells to relax. Frequently prescribed calcium channel blockers include amlodipine (Norvasc), diltiazem (Cardizem, Tiazac, others) and nifedipine (Adalat CC, Afeditab CR, Procardia).