Safety and Tolerability of Azilsartan Medoxomil Plus Chlorthalidone Compared to Olmesartan Medoxomil Plus Hydrochlorothiazide in Participants With Essential Hypertension

High Blood Pressure (Hypertension) is the most common cause of preventable death in developed nations. Uncontrolled hypertension greatly increases the risk of heart disease, brain disease, and kidney failure. As the population ages, the incidence of hypertension will continue to increase if effective preventive measures are not implemented. Despite the availability of antihypertensive agents, hypertension is not adequately controlled; only about one in three patients successfully keep blood pressure normal. Treatment for high blood pressure includes thiazides or thiazide-like diuretics, either alone or as part of combination treatment. Chlorthalidone is a commercially available, orally administered thiazide-type diuretic agent. TAK-491 (azilsartan) is an angiotensin II receptor blocker being evaluated by Takeda to treat patients with high blood pressure (essential hypertension). This study will compare the safety and tolerability of azilsartan medoxomil plus chlorthalidone (TAK-491CLD) fixed-dose combination to olmesartan medoxomil-hydrochlorothiazide fixed-dose combination. Initially patients will undergo a Screening Visit to confirm that they are eligible to participate in the study. All participants will receive the study drug for up to 52 weeks. The dose of the study drug may be gradually increased throughout the study so that a target blood pressure value can be reached for each participant. Throughout the treatment period of the study, participants will be required to visit the research site for 11 visits. At these study visits participants will be required to undergo certain study procedures including physical examinations, vital sign measurements (blood pressure, heart rate, weight and height), electrocardiograms (monitoring of the heart), and blood and urine samples taken for clinical laboratory tests.