What Are Aldosterone Antagonists?

Aldosterone antagonists are potassium-sparing diuretics. They work by blocking the effects of the stress hormone aldosterone.4 Aldosterone receptor antagonists are considered anti-mineralocorticoids, a class of drugs which block the effects of aldosterone, the main mineralocorticoid hormone.3

Aldosterone causes sodium to be reabsorbed by the kidneys, salivary glands, sweat glands, and colon.3 The aldosterone antagonist medications block the effects of aldosterone, which then allows for increased elimination of fluids. This helps to lower blood pressure and reduce fluid buildup around the heart.3

Why are they prescribed?

They are prescribed for people with heart failure and high blood pressure, aldosterone antagonists reduce fluid retention resulting in symptom improvement and helping people to feel better and live longer lives.3 They help to regulate the salt and water balance of the body.3-4 These drugs increase the elimination of these fluids allowing the kidneys to get rid of extra water while retaining necessary potassium.4 This will cause an increased frequency in urination; a reason that diuretics are called water pills.

Aldosterone antagonist drugs are recommended for people with systolic heart failure in addition to other heart failure drugs including ACE inhibitors (or ARBs), beta-blockers and other diuretics.4 They lower blood pressure, ease the workload on the heart, can relieve shortness of breath, and reduce swelling and bloating. Your provider will check blood tests about a week after starting or changing the dose of these medications.

Treatment goals

Treatment goals of aldosterone antagonists include improvement in heart function or delayed progression of heart failure, symptom relief, a decreased risk of hospitalization for heart failure, and a decreased risk of death. They also prevent the kidneys from eliminating too much potassium.2 They are the only diuretics which improve survival outcomes for people with heart failure.4

Commonly prescribed aldosterone antagonists include:1,3-4

  • Aldactone®- (spironolactone)
  • Inspra®- (eplerenone)

Side effects

Common side effects of aldosterone antagonists include muscle weakness, fatigue, or a low heart rate. Some people taking spironolactone may experience breast enlargement or tenderness (gynecomastia), especially in men.2 Medications can take time to work properly and get used to it. It may take a few weeks before both symptoms and side effects go away and you begin to feel better. This is true when starting or changing doses of aldosterone antagonists.4

Aldosterone antagonists may have drug interactions with other medicines you are taking. Be sure to mention to your doctor all medications you are taking, especially if you take potassium supplements and an aldosterone antagonist medication is recommended. Your health care provider will decide whether or not you should continue to take potassium.3-4

As with most heart failure medications, your doctor will generally order regular blood tests to evaluate its effectiveness and any side effects.4 Aldosterone antagonists can cause an increase of potassium in the blood to dangerous levels. If increased potassium levels pose any concerns, modification may need to be made to both diet and drug selection or dosage.1

It is important to take all medicines as prescribed. This will improve the effectiveness of the medication and may reduce any complications. If you have difficulty taking your medications, do not stop on your own, contact your health care team for assistance.

These are not all the possible side effects of aldosterone antagonists. Patients should talk to their doctor about what to expect with treatment with aldosterone antagonists.

If you have trouble breathing, swelling in your face, lips, tongue or throat, or sudden chest pain call 911 or other emergency services or go directly to an emergency room.

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Written by: Linda Minton | Last reviewed: September 2020