Diuretic - Aldosterone Antagonist

Question 1

Name a type of aldosterone antagonist.

Answer 1

Spiralactolone and Eplerenone

Question 2

What is the indication of use for aldosterone antagonist ?

Answer 2

1 - Ascites and Odema due to liver Cirrhosis

2- Chronic Heart Failure

Question 3

What is the Mechanism of Action for Aldosterone Antagonist ?

Answer 3

1- Aldosterone is a mineralocorticoid that is produced in the adrenal cortex.

2- It acts on the mineralocorticoid receptors in the distal convoluted tubes to increase sodium and water reabsorption. This elevates blood pressure and also has a corresponding increase in potassium excretion.

3- Aldosterone antagonists inhibit the effect of aldosterone by competitive inhibition at mineralocorticoid receptors/

4 - THIS INCREASES WATER AND SODIUM EXCRETION AND POTASSIUM RETENSION !!

5 - There effect is greatest when circulating aldosterone is increased eg in cirrhosis.

Question 4

What are some adverse effects of Aldosterone Antagonist ?

Answer 4

• Hyperkalemia
• Gynaecomastia

Question 5

What other drugs cause potassium elevation and, therefore, should be used in caution with aldosterone antagonists?

Answer 5

• ACE inhibators
• Angiotensin Receptor Blockers (ARB)