Olsertain-CT 20 Tablet is a combination antihypertensive medication containing Olmesartan Medoxomil 20mg and Chlorthalidone 12.5mg. Olmesartan Medoxomil is an angiotensin II receptor blocker (ARB) that selectively inhibits the binding of angiotensin II to the AT1 receptor, thereby reducing vasoconstriction and aldosterone secretion, leading to lowered blood pressure. Chlorthalidone is a thiazide-like diuretic that promotes sodium and water excretion by inhibiting sodium reabsorption in the distal convoluted tubules of the kidneys, contributing to a reduction in blood volume and peripheral resistance. The combined effect of these agents provides an effective and complementary approach to managing hypertension, especially in patients requiring multiple mechanisms to achieve optimal blood pressure control. Olsertain-CT 20 is indicated for the treatment of essential hypertension and may be used when monotherapy with either component is insufficient. Its use helps reduce the risk of cardiovascular events such as stroke and myocardial infarction associated with uncontrolled hypertension. Patients should be monitored for electrolyte imbalances, renal function, and blood pressure response during therapy. Olsertain-CT 20 should be used under medical supervision, considering contraindications such as hypersensitivity to components, severe renal impairment, or pregnancy.