Losatan H Tablet is a combination antihypertensive medication containing Losartan 50 mg and Hydrochlorothiazide 12.5 mg. Losartan is an angiotensin II receptor antagonist that selectively blocks the binding of angiotensin II to the AT1 receptor, thereby inhibiting vasoconstriction and aldosterone secretion, which leads to vasodilation and reduction in blood pressure. Hydrochlorothiazide is a thiazide diuretic that promotes sodium and water excretion by inhibiting sodium reabsorption in the distal renal tubules, contributing to decreased blood volume and further lowering of blood pressure. This combination is indicated for the treatment of hypertension, especially in patients who require multiple agents to achieve adequate blood pressure control. The dual mechanism of action provides complementary effects, improving antihypertensive efficacy while minimizing adverse effects associated with higher doses of individual agents. Losatan H Tablet should be used under medical supervision with regular monitoring of blood pressure, electrolytes, renal function, and hydration status. Caution is advised in patients with renal or hepatic impairment, electrolyte imbalances, or a history of hypersensitivity to sulfonamides. Common side effects may include dizziness, hypotension, electrolyte disturbances, and increased urination. This medication is contraindicated during pregnancy and lactation.