Eprosartan mesylate is a nonbiphenyl, nontetrazole, orally active, highly selective, nonpeptide angiotensin-II antagonist used to treat high blood pressure (hypertension) and heart failure. It acts by blocking the effects of angiotensin II, a natural hormone which the body produces in order to increase blood pressure. Blockade of angiotensin II causes easy blood flow by relaxing the blood vessels