Angiotensin-converting enzyme (ACE) inhibitors
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ACE inhibitors combined with diuretic
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How It Works
Angiotensin-converting enzyme (ACE) inhibitors block the activity of an enzyme that causes blood vessels to constrict (narrow). As a result, blood vessels relax and widen (dilate), making it easier for blood to flow through the vessels, which reduces blood pressure.
Preventing blood vessels from narrowing helps improve blood flow, reduces the backup of blood in the heart and lungs, and decreases the pressure that the heart's left chamber (ventricle) must pump against.
These medicines also increase the release of water and salt (sodium) to the urine, which lowers blood pressure. ACE inhibitors (and angiotensin II receptor blockers, also called ARBs) also act directly on the hormones that regulate sodium and water balance in the body.
Why It Is Used
ACE inhibitors affect the body's responses to heart failure.
- ACE inhibitors are commonly used to treat heart failure. They may be the only medicine used for fatigue and mild shortness of breath with no fluid buildup (edema). But in most other cases they are prescribed along with diuretics and a beta-blocker medicine.
- People who do not have symptoms of heart failure (stage A or B), especially those who have recently had a heart attack, benefit from taking ACE inhibitors.
- For people with heart failure, ACE inhibitors have been shown to relieve symptoms, improve clinical status, enhance overall well-being, and reduce the risk of death or hospitalization.
People who should not take ACE inhibitors include:
- People who have had previous adverse reactions to ACE inhibitors.
- People with high potassium levels in the blood that cannot be controlled. These drugs may further increase potassium levels in the blood.
- People with very low blood pressure, especially if their low blood pressure causes dizziness or weakness when they stand up. ACE inhibitors lower blood pressure.
- People with certain kidney problems. ACE inhibitors can make kidney function worse in people who have the kind of kidney disease caused by narrowed blood vessels (renovascular disease).
- Pregnant women.
How Well It Works
In people who have symptoms of heart failure
Enalapril and captopril are the best-studied ACE inhibitors, but other drugs in this class are often effective, also.
When added to conventional therapy (usually diuretics), ACE inhibitors have been shown to:1
- Reduce premature death rates.
- Improve symptoms.
- Slow the progression of heart failure.
- Lower the risk of stroke.
- Slow the progression of many types of chronic kidney disease.
In people who may not have symptoms of heart failure but who have had a heart attack
ACE inhibitors are often started in people who have recently had a heart attack and who have a damaged or weakened left ventricle but who do not yet have symptoms of heart failure. In these people, ACE inhibitors have been found to reduce death rates when started soon after the heart attack.2
Side effects of ACE inhibitors may include:
- A dry cough (common).
- A rash or itching.
- Symptoms like those from allergies.
- An allergic reaction with generalized swelling (angioedema).
- Excess potassium in the body (hyperkalemia), especially in people with kidney failure.
- Low blood pressure, especially when first starting on ACE inhibitor medicine.
- Kidney problems.
ACE inhibitors may interact with nonsteroidal anti-inflammatory drugs (NSAIDs), antacids, potassium supplements, certain diuretics, and lithium. If you are taking one of these medicines, talk with your doctor before taking any other medicines.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Usually, ACE inhibitors cause very few side effects. The most common side effect is an irritating dry cough. Most people find the cough to be a minor problem that they can live with in exchange for the benefits of this medicine. If you take an ACE inhibitor and have a problem with coughing, then you might take an angiotensin II receptor blocker (ARB) instead. ARBs are less likely to cause a cough. ARBs have been shown to work as well as ACE inhibitors for heart failure.3
ACE inhibitors are one of the first choices in drugs for treating heart failure.
- Heart Failure Society of America (2006). HFSA 2006 comprehensive heart failure practice guidelines: Executive summary. Journal of Cardiac Failure, 12(1): 10–38. Also available online: http://www.abouthf.org/guidelines.htm.
- Hunt SA, et al. (2009). 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of heart failure in adults. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation, 119(14): e391–e479.
- McKelvie R (2008). Heart failure, search date January 2007. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
Last Updated: August 25, 2008