Losacar-H Tablet contains a combination of Losartan 50 mg and Hydrochlorothiazide 12.5 mg, used primarily for the management of hypertension. Losartan is an angiotensin II receptor antagonist that selectively blocks the binding of angiotensin II to the AT1 receptor, leading to vasodilation, reduced secretion of aldosterone, and decreased blood pressure. Hydrochlorothiazide is a thiazide diuretic that promotes the excretion of sodium and water by inhibiting sodium reabsorption in the distal convoluted tubules of the kidneys, thereby reducing blood volume and peripheral vascular resistance. The synergistic effect of these two agents provides enhanced antihypertensive efficacy compared to monotherapy. Losacar-H is indicated for patients whose blood pressure is not adequately controlled with Losartan alone. It is important to monitor electrolyte levels, renal function, and blood pressure regularly during treatment. Contraindications include hypersensitivity to either component, anuria, or severe renal impairment. Caution is advised in patients with a history of gout, diabetes, or electrolyte imbalances. Common adverse effects may include dizziness, hypotension, hyperkalemia, or electrolyte disturbances. This combination therapy should be used under medical supervision to optimize therapeutic outcomes and minimize potential risks.