How Does Quinapril Work?Quinapril is part of a class of drugs called ACE inhibitors. ACE stands for angiotensin-converting enzyme. Quinapril helps to block the angiotensin-converting enzyme, which is normally part of a reaction in the body that causes blood vessels to narrow (constrict). By blocking this enzyme, quinapril causes blood vessels to relax, which can lower blood pressure.
By helping blood vessels relax, quinapril also increases the efficiency of the heart. This means that the heart does not have to work as hard and more blood can be pumped out to the rest of the body. Both of these are helpful for a person with congestive heart failure.