Angiotensin Converting Enzyme (ACE) Inhibitors

What is an angiotensin converting enzyme (ACE) inhibitor?

ACE inhibitors are drugs that help relax blood vessels. Relaxing blood vessels allows blood to flow more easily and lowers the blood pressure. Lowering the blood pressure reduces or prevents heart attacks or strokes and makes it easier to treat heart failure. Heart failure occurs when the heart is either too weak or too damaged to pump blood properly. ACE inhibitors appear to decrease the amount of damage to the heart muscle following a heart attack.


Lisinopril, captopril, ramipril, and trandolapril are examples of ACE inhibitors. Which one is best for you depends on your condition and health.

How do ACE inhibitors work?

Angiotensin converting enzyme (ACE) is a substance in the body that converts an inactive blood chemical to a very active blood vessel constrictor, or "squeezer." Blood vessel constrictors narrow the internal diameter of blood vessels. The body uses ACE to help regulate the blood pressure. It makes the blood vessels constrict when blood pressure needs to be higher. In some people with high blood pressure (hypertension) the enzyme is overactive. This can cause high blood pressure and increase the workload of the heart and other organs. ACE inhibitors reduce the activity of this enzyme.

When are ACE inhibitors used?

High blood pressure (hypertension) and heart failure are the most common reason for the use of ACE inhibitors. The drugs may be used alone or with other drugs.


ACE inhibitors are used to treat heart failure. Poor pumping ability of the heart leads to buildup of fluid in body tissues and the lungs. Symptoms such as fatigue, swelling of the legs and ankles, and shortness of breath are common. ACE inhibitors relieve these symptoms by reducing blood pressure to ease the workload of the heart.


ACE inhibitors have been shown to limit muscle damage done to the heart by a heart attack. These drugs help the heart heal in a normal shape after a heart attack so it can pump better. They can help prevent heart attacks in people who are at high risk.


ACE inhibitors also work on the kidneys by reducing the tendency of the body to retain fluids. They can help prevent kidney problems in people with diabetes.

What should be monitored while taking ACE inhibitors?

Your health care provider will check your blood pressure regularly. Checks of your blood potassium level may be necessary. If you have heart failure, you also need to limit your salt intake and to weigh yourself regularly.


Report these side effects to your health care provider right away:

  • a dry, hacking cough
  • severe dizziness or fainting
  • skin rashes
  • muscle weakness
  • swelling of the tissues in your face, eyes, lips, tongue, or throat, especially if it interferes with breathing.

Not all of the ACE inhibitors have the same side effects. If you develop symptoms while on the drug, contact your health care provider right away. Fortunately, most people taking the drug have no symptoms.


Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.


HIA File MED4250F.HTM Release 9.0/2006

Copyright © 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.

Copyright © 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.