John Caudle,   Thanks for your question.    Enalapril (brand name - Vasotec) is an Angiotensin converting enzyme inhibitor.  This drug blocks the production of a powerful hormone that constricts blood vessels and promotes the retention of water and salts in the urine.  The use of this medication causes blood vessels to dilate and therefore lower blood pressure.    This medication is used for the treatment of high blood pressure and some heart conditions such as congestive heart failure and aortic valve insufficiency.    I hope this information has been helpful.  Best wishes.   Martin Cane, M.D.