Irbesartan 150 Mg + Hydrochlorothiazide 12.5 Mg TabletsAnti-Hypertensive DrugsIrbesartan is an angiotensin II receptor blocker (ARB). It works by blocking a substance in the body that causes blood vessels to constrict. As a result, irbesartan relaxes the blood vessels. This lowers blood pressure and increases the supply of blood anHydrochlorothiazide inhibits sodium chloride transport in the distal convoluted tubule. More sodium is then excreted in the kidney with accompanying fluid. Thus it increases urine excretion, which by turn decreases blood volume and finally blood pressure.