A student nurse is preparing an IV push dose of furosemide 80 mg. Which lab value would cause the student to question administering the medication?

Choice A reason: A potassium level of 3.0 mEq/L indicates hypokalemia, a concern with furosemide, a loop diuretic that increases potassium excretion in urine. Administering furosemide could worsen hypokalemia, risking arrhythmias and muscle weakness, as potassium is critical for cardiac and neuromuscular function, prompting the nurse to question administration. Choice B reason: A phosphorus level of 4.0 mg/dL is within normal range (2.5–4.5 mg/dL) and does not contraindicate furosemide administration. Furosemide primarily affects potassium, sodium, and water balance, with minimal direct impact on phosphorus, making this lab value irrelevant to the decision to administer the drug. Choice C reason: A sodium level of 145 mEq/L is at the upper limit of normal (135–145 mEq/L) and does not contraindicate furosemide, which promotes sodium excretion. While furosemide may lower sodium levels, this value is not critical enough to halt administration, as it poses no immediate risk. Choice D reason: A calcium level of 10.2 mg/dL is within normal range (8.5–10.5 mg/dL) and does not affect furosemide administration. Furosemide can increase calcium excretion, but this value is not abnormal, and hypocalcemia is not a primary concern compared to potassium imbalances with this medication.