How Do Aldosterone Antagonists Work?

Aldosterone antagonists (antimineralocorticoid or mineralocorticoid receptor antagonists) are diuretics or "water pills" used for the treatment of high blood pressure or heart failure. They work by inhibiting the effects of aldosterone, a mineralocorticoid hormone secreted by the adrenal gland. Aldosterone release causes retention of sodium and water, which causes increased blood volume, and a subsequent increase in blood pressure.

Aldosterone receptor antagonists block the effects of aldosterone. This causes reabsorption of sodium by the kidneys and other glands, which encourages water loss, and a subsequent decrease in blood pressure and reduction in fluid around the heart.

Aldosterone may also cause myocardial fibrosis, leading to cardiac hypertrophy (abnormal enlargement, or thickening, of the heart muscle) and remodeling. It can also directly alter the function of the internal layer of the blood vessels (endothelium) by reducing the availability of nitric oxide. Nitric oxide widens the blood vessels, and in its absence, blood vessels cannot dilate and this leads to an increase in blood pressure.

Aldosterone antagonists decrease myocardial collagen formation, normalize the heart rate, improve endothelial function, and increase basal nitric oxide bioactivity.

Aldosterone antagonists are used to treat:

• Congestive heart failure
• High blood pressure
• Ascites (abdomen swelling caused by fluid accumulation) due to cirrhosis and portal hypertension (increase in pressure of portal vein which carries blood from the digestive organs)
• Hypokalemia (low potassium level)

Off-label use includes hirsutism (unwanted male-pattern hair growth on a woman's face, chest and back) and acne.

Side effects associated with aldosterone antagonists include:

• Hyperkalemia (increased potassium levels)
• Hyperchloremic metabolic acidosis (a pathological state that results from bicarbonate loss)
• Acute renal failure
• Kidney stones
• Antiandrogenic effects (such as gynecomastia-enlargement or swelling of breast tissue in males)
• Reversible decline in glomerular filtration rate
• Upper gastrointestinal side effects

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:

• Aldactone
• CaroSpir
• Eplerenone
• Finerenone
• Inspra
• Spironolactone