Capoten Captopril tablets What do captopril tablets do?CAPTOPRIL (Capoten(R)) is an antihypertensive (blood pressure lowering agent) known as an ACE inhibitor. Captopril controls high blood pressure (hypertension) by relaxing blood vessels; it is not a cure. High blood pressure levels can damage your kidneys, and may lead to a stroke or heart failure. Captopril also can help to treat heart failure (heart does not pump strongly enough) and certain kidney disorders. Generic captopril tablets are available.