Pharmacology of Potassium-Sparing Diuretics

Mechanism of Action:

Potassium-sparing diuretics act on the collecting ducts in the kidneys. They inhibit sodium reabsorption while reducing potassium secretion, effectively sparing potassium levels in the body.

#Potassium-sparing diuretics MOA

There are two main types:

  1. Aldosterone Antagonists: Block the action of aldosterone, a hormone that promotes sodium reabsorption and potassium excretion.
  2. Sodium Channel Blockers (epithelial): Directly inhibit sodium channels in the collecting ducts.


  • Absorption: Variable oral absorption.
  • Distribution: Limited distribution; some are protein-bound.
  • Metabolism: Liver metabolism for some agents like spironolactone.
  • Excretion: Primarily renal excretion.

Drug Examples:

  • Spironolactone (Aldactone): Aldosterone antagonist; also has anti-androgenic effects.
  • Eplerenone (Inspra): Selective aldosterone antagonist.
  • Amiloride: Sodium channel blocker.
  • Triamterene: Sodium channel blocker.

Clinical Use:

  1. Hypokalemia: To prevent or treat low potassium levels.
  2. Heart Failure: Often used in combination with other diuretics.
  3. Ascites: In liver disease to prevent hypokalemia.
  4. Hyperaldosteronism: To counteract the effects of high aldosterone levels.

Side Effects:

  • Hyperkalemia: High potassium levels
  • Gynecomastia: With spironolactone use
  • Renal impairment: Risk of acute kidney injury
  • Acid-base imbalances

Drug Interactions:

  • ACE Inhibitors: Increased risk of hyperkalemia.
  • Potassium Supplements: Increased risk of hyperkalemia.
  • NSAIDs: Reduced diuretic effect.


  • Severe renal impairment.
  • Hyperkalemia.
  • Known hypersensitivity to the drug.

Understanding the pharmacology of potassium-sparing diuretics is essential for healthcare providers to effectively treat conditions like hypokalemia and heart failure while minimizing side effects.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always seek the advice of a healthcare provider with any questions regarding a medical condition.

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