Rezor 20 mg Tablet contains Olmesartan Medoxomil, an angiotensin II receptor blocker (ARB) manufactured by Renata Limited. It is primarily used to treat high blood pressure (hypertension). By blocking the action of angiotensin II, a substance that constricts blood vessels, Olmesartan helps to relax and widen blood vessels, thereby lowering blood pressure and reducing the risk of stroke and heart attack.