Hydrochlorothiazide (HCT) is a well-established diuretic and antihypertensive agent, which promotes natruresis by acting on the distal renal tubule. Metoprolol succinate extended-release tablet is a beta-1 (cardio-selective) adrenoceptor-blocking agent formulated to provide controlled and predictable release of metoprolol. Given the heterogeneity of hypertension as a disease, the marked variability in an individual patient’s BP response, and low response rates with monotherapy, expert groups such as the Joint National Committee (JNC) emphasize the value of combination antihypertensive regimens, noting that combinations, usually of different classes, have additive antihypertensive effects. Lowering elevated blood pressure (BP) with drug therapy reduces the risk for catastrophic fatal and nonfatal cardiovascular events such as stroke and myocardial infarction.