Tri-Olmetor 40 Tablet is a combination of three medicines: Olmesartan Medoxomil, Amlodipine and Hydrochlorothiazide. Olmesartan Medoxomil is an angiotensin receptor blocker (ARB) and Amlodipine is a calcium channel blocker (CCB). They work by widening and relaxing the blood vessels, thereby lowering blood pressure. Hydrochlorothiazide is a diuretic which removes extra water and certain electrolytes from the body through urine. Over time it also works by relaxing blood vessels and improving blood flow.