ACE inhibitors block production of an enzyme that helps convert the protein angiotensin 1 into angiotensin 2, a protein that makes blood vessels constrict and promotes retention of fluid, raising blood pressure. ACE inhibitors act to widen the blood vessels and make it easier for the heart to pump blood through the body. Captopril (Capoten), ramipril (Altace), and enalapril (Vasotec) are commonly used ACE inhibitors