Topic 6B: Cardiovascular Drugs - Diuretics

Overview

• Professor Hoffman
• Focus: Diuretics
  • Loop Diuretics
  • Thiazide Diuretics
  • Aldosterone Inhibitors / Potassium-Sparing Diuretics

Diuretics

• Function: Increase urine output
• Mechanism: Increase excretion of sodium (Na²⁺) and chloride (Cl⁻)
• Main Indications:
  • Hypertension (HTN)
  • Edema (peripheral or pulmonary)

Classes of Diuretics

1. Loop Diuretics

• Examples: Furosemide (Lasix), Bumetanide (Bumex), Torsemide (Demadex)
• Site of Action: Loop of Henle in kidneys
• Mechanism:
  • Excretion of sodium (Na²⁺) and chloride (Cl⁻)
  • Leads to water (H₂O) excretion
  • Loss of potassium (K⁺) and calcium (Ca²⁺)
• Uses:
  • Edema (peripheral or pulmonary, chronic or acute)
  • Hypertension (quick response)
• Adverse Effects:
  • Cellular dehydration
  • Electrolyte depletion (Na²⁺, K⁺, Ca²⁺)
  • Ototoxicity (when administered too quickly IV)
  • Potential for kidney impairment
• Nursing Considerations:
  • Monitor blood pressure (BP), electrolytes (particularly K⁺ and Ca²⁺)
  • Ensure patient maintains potassium-rich diet or supplements
  • Assess for dehydration
  • Monitor weight (1 kg of weight loss = ~1 liter of fluid loss)

2. Thiazide and Thiazide-like Diuretics

• Examples: Often end in -thiazide
• Site of Action: Distal convoluted tubule
• Mechanism:
  • Excretion of sodium (Na²⁺) and chloride (Cl⁻)
  • Leads to water (H₂O) excretion
  • Loss of potassium (K⁺)
  • Calcium (Ca²⁺) retention
• Uses:
  • Hypertension
  • Edema (less immediate response)
• Adverse Effects:
  • Electrolyte depletion (Na²⁺, K⁺)
  • Calcium retention (hypercalcemia)
  • Risk of dehydration
  • Potential hypersensitivity responses
• Nursing Considerations:
  • Monitor blood pressure, electrolytes (particularly K⁺ and Ca²⁺)
  • Ensure kidney function
  • May need potassium supplements

3. Aldosterone Inhibitors / Potassium-Sparing Diuretics

• Examples: Spironolactone (Aldactone)
• Mechanism:
  • Blocks aldosterone in distal convoluted tubule
  • Prevents sodium (Na²⁺) retention
  • Retains potassium (K⁺)
• Uses:
  • Hypertension
  • Edema (adjunct with thiazide or loop diuretics)
  • Heart failure (maintains K⁺ levels)
• Adverse Effects:
  • Hyperkalemia (high potassium levels)
  • Cellular dehydration
  • Hypotension
  • Possible hypersensitivity responses (rare)
• Nursing Considerations:
  • Monitor blood pressure, particularly for hyperkalemia
  • Assess kidney function
  • Be cautious with potassium intake from other sources (diet, supplements)

Summary

• Each diuretic class has specific mechanisms, uses, and nursing considerations, particularly focusing on electrolyte balance and kidney function.