Aldosteron-antagonists

Aldosterone antagonists include:

• Spironolactone
• Eplerenone

Aldosterone antagonists are drugs used to flush out fluid in various diseases, particularly heart failure with edema, liver cirrhosis with ascites, and Conn's syndrome.

Aldosterone antagonists (e.g. eplerenone) bind to mineralocorticoid receptors. As a result, the blood pressure-increasing hormone aldosterone can no longer dock to these receptors and is therefore ineffective. This suppresses the aldosterone-mediated effects, i.e. the excretion of salt and water is increased. Blood volume decreases and the heart is unloaded. At the same time, potassium retention occurs. Thus, more potassium is available to the weakened heart muscle and the contractility is strengthened.

Furthermore, the concentration of free aldosterone in the body increases. This in turn causes the adrenal glands to reduce or completely stop aldosterone production. At the same time, less renin is produced in the kidneys . This endopeptidase is at the beginning of the blood pressure regulating renin-angiotensin-aldosterone system (RAAS). Overall, the blood pressure is lowered, the heart muscles are strengthened and the heart is relieved.

Aldosterone antagonists act at the distal tubule of the kidneys by increasing the excretion of sodium ions along with the solution water. Potassium is retinated by counter-exchange. Potassium retention can be compensated for by combination with other diuretics (e.g. loop diuretics or thiazides). They reduce mortality in severe heart disease.

Spironolactone is not a selective AR antagonist. It also acts as an antagonist of progesterone and androgen receptors. This explains some of the known side effects such as gynecomastia, impotence and menstrual cramps.

Main indications for aldosterone antagonists are

• Heart failure
• liver cirrhosis with hyperaldosteronism
• other forms of secondary hyperaldosteronism
• primary hyperaldosteronism (Conn syndrome)
• protection of the heart in heart failure