A: Zestril/Prinivil (lisinopril) is an ACE (angiotensin converting enzyme) inhibitor, used to treat hypertension (high blood pressure), CHF (congestive heart failure), and to improve survival after a heart attack, and incontinence is not a listed side effect.: Lisinopril is a medication that is used to treat high blood pressure. It is in a class of medications called ACE inhibitors. ACE is a chemical in the body that is used in a chemical reaction that causes our blood vessels to narrow in response to various conditions.