Olsar-H 20 Tablet is a combination antihypertensive medication containing Olmesartan Medoxomil 20 mg and Hydrochlorothiazide 12.5 mg. Olmesartan Medoxomil is an angiotensin II receptor antagonist that selectively blocks the binding of angiotensin II to the AT1 receptor, thereby inhibiting vasoconstriction and aldosterone secretion, leading to vasodilation and reduction of blood pressure. Hydrochlorothiazide is a thiazide diuretic that promotes diuresis by inhibiting sodium reabsorption in the distal convoluted tubules of the kidneys, resulting in decreased plasma volume and peripheral vascular resistance. The combination of these two agents provides complementary mechanisms to effectively control hypertension, reducing the risk of cardiovascular events such as stroke and myocardial infarction. Olsar-H 20 is indicated for the treatment of essential hypertension in patients who require more than one antihypertensive agent to achieve optimal blood pressure control. It is contraindicated in patients with hypersensitivity to any component, anuria, or severe renal impairment. Caution is advised in patients with electrolyte imbalance, renal or hepatic dysfunction, and during pregnancy. Regular monitoring of blood pressure, renal function, and electrolytes is recommended during therapy. This medication should be used under medical supervision to ensure safety and efficacy.