Furosemide and Potassium Loss

Renal & Electrolytes · Question from the ATI RN Medical-Surgical 2023 Proctored Exam study set

Correct answer: C. Hypokalemia

Why this is the answer

Loop diuretics like Furosemide block sodium and chloride reabsorption in the loop of Henle, and that increased flow downstream causes the kidneys to excrete potassium along with it — leading to low serum potassium (hypokalemia). Hyperkalemia (A) is the opposite of what happens; loop diuretics waste potassium rather than retain it. Hyponatremia (B) is possible with diuretic use but isn't the classic, most-tested risk paired with loop diuretics the way potassium loss is. Hypercalcemia (D) is also backwards — loop diuretics actually increase calcium excretion (unlike thiazide diuretics, which spare calcium), so if anything they trend a patient toward low, not high, calcium.

The bigger concept

Any time a patient is on a loop diuretic, potassium monitoring is a priority — this is especially critical if the patient is also on Digoxin, since hypokalemia significantly raises the risk of digoxin toxicity. Nurses should expect potassium supplementation or a potassium-sparing add-on to be part of the care plan.

Related Renal & Electrolytes practice questions

• Managing High Phosphorus in Chronic Renal Failure
• What Chvostek's Sign Reveals About Calcium
• High Magnesium in Renal Failure: What to Monitor
• Positive Trousseau's Sign: What It Means
• Why Anemia Is Common in Chronic Renal Failure

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