Potassium-Sparing Diuretics (Aldosterone Inhibiting)

Mechanism of Action

• Site of Action: Distal tubule.
• Function: Blocks aldosterone receptors.
  • Interferes with sodium (Na) and potassium (K) exchange.
  • Increases sodium and water (H2O) excretion while retaining potassium and hydrogen.

Aldosterone Overview

• Role: Steroid hormone produced by adrenal glands.
  • Essential for sodium conservation in kidneys.
  • Promotes retention of sodium and water.
  • Aids in potassium excretion.
• Inhibition Effects:
  • Not conserving sodium and water.
  • Potassium sparing (retains potassium).

Therapeutic Effects

• Diuresis: With less potassium excretion.
• Blockade: Effects of aldosterone (sodium and water excretion, potassium retention).

Indications for Use

• High blood pressure (hypertension).
• Fluid overload or edema.
• Hyperaldosteronism (excess aldosterone).
  • Causes low potassium levels and hypertension due to sodium and water retention.

Precautions

• Impaired renal function (drug is excreted renally).
• Pre-existing dehydration:
  • Pulling off fluid can worsen dehydration.
• Pre-existing electrolyte disturbances.

Electrolyte Concerns

• Hyperkalemia: Elevated potassium levels.
  • Potassium levels > 5.5 are critical.
  • Important to monitor in clinical settings.

Side and Adverse Effects

• Electrolyte Disturbances: Hyperkalemia.
• Other Effects: Weakness and dizziness due to volume depletion.

Nursing Actions

• Caution: Use with ACE inhibitors.
  • Both can cause elevated potassium levels.
  • Monitor potassium levels closely.
• Combination Therapy:
  • Combining loop diuretics with potassium-sparing diuretics.
  • Promotes diuresis while reducing the risk of hypokalemia.

Example of Drug in Class

• Prototype: Spironolactone.