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A 28-year-old woman with chronic renal failure ...


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submitted by hungrybox(256),

Loop diuretics are first line for acute congestive heart failure. That should help you remember that they are the most potent diuretics, so they're often used in the acute treatment of edema.

Chronic renal failure = High potassium in blood (page 590 FA19) Furosamide is the strongest diuretic on that list that also depletes Potassium

claptain  HCTZ and acetazolamide would also deplete potassium, they are just not as strong of diuretics. To be potassium-sparing, it has to have effect at the collecting ducts. Any diuretic that works before the collecting ducts will increase the concentration of sodium going to the collecting ducts and stimulate sodium/potassium exchange at the collecting ducts, potentially leading to decreases in potassium +  

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submitted by mcl(232),

Furosemide and other loop diuretics are indicated for use in volume overload secondary to renal failure. Recall loop diuretics inhibit the Na+/K+/Cl- pump at the thick ascending loop of Henle, which messes with the hypertonicity of the medulla and therefore prevents urine from being concentrated. This results in increased fluid loss to urine, and is helpful in treating symptoms of edema.

at my uni, we learnt that at lower GFR, loop diuretics still work. That's why you should use them in renal failure. Thiazides would not work with a GFR of <30.