Eritel-Trio Tablet is a combination antihypertensive medication containing Telmisartan 40mg, Amlodipine 5mg, and Hydrochlorothiazide 12.5mg. This formulation is designed to provide effective blood pressure control through complementary mechanisms of action. Telmisartan, an angiotensin II receptor blocker (ARB), selectively inhibits the binding of angiotensin II to the AT1 receptor, resulting in vasodilation and reduced aldosterone secretion, thereby lowering blood pressure. Amlodipine, a dihydropyridine calcium channel blocker, relaxes vascular smooth muscle by inhibiting calcium influx, leading to decreased peripheral resistance. Hydrochlorothiazide, a thiazide diuretic, promotes sodium and water excretion by inhibiting sodium reabsorption in the distal convoluted tubules of the kidneys, reducing plasma volume and cardiac output. The combination of these agents targets multiple pathways involved in hypertension pathophysiology, enhancing antihypertensive efficacy and improving patient compliance by reducing pill burden. Eritel-Trio is indicated for the treatment of essential hypertension in patients who require multiple antihypertensive agents to achieve adequate blood pressure control. It should be used under medical supervision with regular monitoring of renal function, electrolytes, and blood pressure to minimize potential adverse effects such as hypotension, electrolyte imbalance, or renal impairment.