Angiotensin-converting enzyme inhibitors (also called ACE inhibitors) are medicines, Angiotensin-converting enzyme inhibitors block the conversion of the chemical angiotensin I to a substance that increases salt and water retention in the body. ACE inhibitors are available only with a physician's prescription and come in tablet, capsule, and injectable forms. Some commonly used ACE inhibitors are benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace) and trandolapril (Mavik).