How ACE Inhibitors Treat Heart Failure

doctor talking to female patient about medication
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Angiotensin-converting enzyme (ACE) inhibitors are the first line of defense in treating congestive heart failure (CHF), a life-threatening condition in which the heart does not pump sufficient blood to the organs.

How They Work 

Used successfully for more than 20 years, ACE inhibitors slow the progression of CHF in three ways:

  • They block an enzyme that constricts blood vessels, which reduces blood pressure and delivers more blood to the heart, making it work easier.
  • They lower the amount of salt and water in the body, which also decreases blood pressure.
  • They prevent the production of a substance called angiotensin, which makes vessels tighten and raises blood pressure.


ACE inhibitors, such as Vasotec (enalapril) and Capoten (captopril), are most commonly prescribed for heart failure to decrease the chances of heart attack and stroke.

For years, combination treatments for heart therapy - pairing ACE inhibitors with angiotensin II receptor blockers (ARBs) - was the preferred method. But a 2007 article in the American Diabetes Association's DOC News maintained that women, in particular, derive greater benefit from ARBs. Subsequently, a comprehensive 2008 study in the New England Journal of Medicine upheld the effectiveness of ACE inhibitors, with ARBs remaining an option for some.

Side Effects and Drug Interactions

At first, patients may be told to take the drug at bedtime to minimize any initial dizziness resulting from lowered blood pressure. Other relatively common side effects include:

  • Persistent, dry cough
  • Weakness, dizziness
  • Upset stomach, poor appetite
  • Skin rashes
  • Metallic taste in the mouth
  • High potassium levels
  • Nausea and headaches

Rare Side Effects

Rare side effects include hoarseness, fever, chills, facial swelling and severe upset stomach. Tell your doctor if you experience any of these, but don't stop taking the medication on your own. ARBs such as Cozaar (losartan) may be prescribed for patients who have severe reactions to ACE inhibitors.

Women who are pregnant or breastfeeding, or those planning to become pregnant, should not take ACE inhibitors. Also, if you have diabetes, lupus, or heart, kidney or liver disease, or if you've had a recent heart attack or kidney transplant, your doctor may not want to prescribe ACE inhibitors.

Combining ACE inhibitors and alcohol can result in dangerously low blood pressure. Certain herbal supplements and medicines, including diuretics (water pills) and drugs containing potassium, can also affect the action of ACE inhibitors. Make sure the doctor who prescribes your ACE inhibitors has a complete list of all your other medications.

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Article Sources
  • "ACE Inhibitors: Summary of Recommendations." 2008. Consumers Union.
  • "Angiotensin-Converting Enzyme (ACE) Inhibitors." Jul. 2007. Texas Heart Institute.
  • The PEACE Trial Investigators. "Angiotensin-Converting--Enzyme Inhibition in Stable Coronary Artery Disease." New England Journal of Medicine 351:20(2004):2058-68.
  • Law, Bridget Murray. "ARBs Outperform ACE Inhibitors in Women With Heart Failure." DOC News 4:11(2007): 10. American Diabetes Association.
  • "Medications Commonly Used to Treat Heart Failure." 9 Jan. 2008. American Heart Association.
  • Scow, Dean Thomas, Ellen G. Smith, and Allen F. Shaughnessy. "Combination Therapy With ACE Inhibitors and Angiotensin-Receptor Blockers in Heart Failure." American Family Physician 68:9(2003):1795-98. 4 Nov. 2008. .
  • The ONTARGET Investigators. "Telmisartan, Ramipril, or Both in Patients at High Risk for Vascular Events." New England Journal of Medicine 358:15(2008): 1547-59. 4 Nov. 2008.