Final answer:
The nurse should question the prescription of spironolactone (Aldactone) for a patient with high serum potassium levels. Alternatives such as furosemide (Lasix), hydrochlorothiazide, or mannitol would be more suitable due to their potassium-lowering effects.
Step-by-step explanation:
If a patient has edema of the lower extremities, fluid in the lungs (indicative of congestive heart failure or similar conditions), and a high serum potassium level (5.8 mEq/L which indicates hyperkalemia), the nurse should question the prescription of a potassium-sparing diuretic like spironolactone (Aldactone). Spironolactone is known to conserve potassium, and prescribing it to a patient who already has high potassium levels could be dangerous. On the other hand, loop diuretics like furosemide (Lasix) and thiazide diuretics such as hydrochlorothiazide (HydroDIURIL), as well as osmotic diuretics like mannitol (Osmitrol), generally act to decrease potassium levels and would be more appropriate in this situation.