multi class comparison
Diuretic Classes Comparison
Diuretics are among the most frequently prescribed medications in nursing practice, but each class works on a different part of the nephron with dramatically different effects on electrolytes. Confusing their mechanisms and side effects is a common NCLEX trap.
Comparison
| Feature | Loop Diuretics | Thiazide Diuretics | Potassium-Sparing |
|---|---|---|---|
| Examples | Furosemide (Lasix), bumetanide | Hydrochlorothiazide (HCTZ) | Spironolactone, triamterene |
| Site of action | Loop of Henle | Distal convoluted tubule | Collecting duct |
| Potency | Most potent | Moderate | Mild |
| Potassium effect | Depletes K+ (hypokalemia risk) | Depletes K+ (hypokalemia risk) | Retains K+ (hyperkalemia risk) |
| Sodium effect | Significant Na+ loss | Moderate Na+ loss | Mild Na+ loss |
| Calcium effect | Increases Ca++ excretion | Decreases Ca++ excretion | Minimal effect |
| Common use | Acute HF, pulmonary edema, renal failure | HTN, chronic edema, osteoporosis | HF (with ACEi), aldosteronism |
| Key side effect | Ototoxicity (especially IV push) | Hyperglycemia, hyperuricemia | Gynecomastia (spironolactone) |
| Timing | AM dose (and noon if BID) | AM dose | Can give anytime |
| Critical monitoring | K+, hearing, renal function | K+, glucose, uric acid | K+ (watch for hyperkalemia) |
Clinical Pearl
The most tested diuretic interaction: loop diuretics + digoxin. Furosemide depletes potassium, and hypokalemia potentiates digoxin toxicity. If a patient is on both medications, potassium monitoring is critical. Also remember that potassium-sparing diuretics + ACE inhibitors is a dangerous combination for hyperkalemia — both retain potassium through different mechanisms.
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