Loop Diuretics Lecture Notes

Introduction

• Lecture by Sarah from RegisteredNurseAriene.com
• Focus on loop diuretics as part of pharmacology series
• Use acronym 'NURSE' to understand key concepts:
  • N: Name and family of the drug
  • U: Usage and what it treats
  • R: Nurse responsibilities
  • S: Side effects
  • E: Patient education

Name and Mechanism of Action

• Loop Diuretics: Affect how the loop of Henle works within the nephron, specifically the thick ascending limb.
• Mechanism: Inhibit sodium reabsorption, increasing urinary output.
• Examples: Bumetanide, Furosemide, Torsemide (end in "-nide" or "-mide"). Exception: ethacrynic acid.

Nephron Anatomy and Physiology

• Nephron Function: Filters blood, manages water, ions, and waste.
• Key Parts of the Nephron:
  • Afferent arteriole: Delivers blood to nephron
  • Efferent arteriole: Returns filtered blood
  • Glomerulus: Filters blood, creates filtrate
  • Proximal convoluted tubule: Tweaks filtrate in isotonic environment
  • Loop of Henle: Descending limb (permeable to water), ascending limb (permeable to ions)
  • Distal convoluted tubule and collecting duct: Further tweak filtrate

Loop Diuretics Mechanism

• Thick Ascending Limb: Loop diuretics block sodium-potassium-chloride transporter.
• Tonicity Alteration: Decreased tonicity inhibits water reabsorption, increasing urinary output.

Uses of Loop Diuretics

• Treat fluid volume overload conditions:
  • Heart failure, liver impairment (ascites), pulmonary edema
• Hypertension: Less effective than thiazides but used occasionally
• Hypercalcemia: Lowers blood calcium levels by affecting ion transport

Nurse Responsibilities and Side Effects

• Dehydration Risk: Monitor fluid status (vital signs, intake/output, daily weights)
• Electrolyte Imbalance:
  • Monitor potassium (risk of hypokalemia), magnesium, sodium
  • Check for digoxin toxicity if patient is on digoxin
• Other Side Effects:
  • Metabolic alkalosis
  • Increased uric acid levels (gout risk)
  • Ototoxicity (prevent by slow IV administration)

Patient Education

• Recognize dehydration symptoms: excessive thirst, lethargy, low urine output
• Monitor blood pressure and heart rate
• Diet: Include potassium-rich foods (potatoes, avocados, bananas, spinach)
• Safety: Change positions slowly to prevent falls due to orthostatic hypotension
• Daily Weights: Track and report significant weight changes

Conclusion

• Review of loop diuretics and their effect on nephrons, patient treatment, and nurse roles
• Encourage taking the free quiz and subscribing for more content