Which diuretic is better suited for renal impairment?

• A. Loop diuretics
• B. Thiazide
• C. Potassium-sparing
• D. Carbonic Anhydrase inhibitors

Answer: (A)

In renal impairment you want a diuretic that still works when filtration is reduced. Loop diuretics fit this best because they block the Na-K-2Cl cotransporter in the thick ascending limb, delivering a strong natriuresis that remains effective even with low GFR. This makes them the go-to choice for volume overload or edema when kidney function is diminished. Thiazides rely on adequate filtered fluid and tend to lose much of their effect as GFR falls, while carbonic anhydrase inhibitors are relatively weak diuretics with limited use in kidney disease, and potassium-sparing diuretics are milder and mainly used for specific indications like preventing potassium loss.