Losart Plus 100/12.5 mg is a fixed-dose combination tablet containing two antihypertensive agents: Losartan Potassium and Hydrochlorothiazide. Losartan is an angiotensin II receptor blocker (ARB) that selectively inhibits the binding of angiotensin II to the AT₁ receptor, leading to vasodilation and reduced blood pressure. Hydrochlorothiazide is a thiazide diuretic that works by increasing the excretion of sodium and chloride in the distal convoluted tubules of the kidney, resulting in decreased blood volume and lower blood pressure. This combination is indicated for the treatment of hypertension, particularly in patients whose blood pressure is not adequately controlled with monotherapy. The usual starting dose is one tablet once daily, with adjustments based on the patient's response and tolerability. Common side effects may include dizziness, fatigue, and elevated potassium levels. It is contraindicated in patients with hypersensitivity to any component of the product, anuria, or hypersensitivity to other sulfonamide-derived drugs. Caution is advised in patients with renal or hepatic impairment, and regular monitoring of blood pressure and electrolytes is recommended during treatment