What should you closely monitor when giving furosemide?

• A. Potassium
• B. Blood pressure
• C. BUN
• D. Creatinine

Answer: (A)

Furosemide is a loop diuretic, which means it causes a large amount of sodium and water to be excreted in the urine. Along with this, it increases potassium loss in the distal nephron, making hypokalemia a common and potentially dangerous side effect. Potassium is essential for maintaining normal cardiac conduction, so dropping potassium levels can lead to arrhythmias, especially in patients who are also on medications like digoxin. For that reason, closely monitoring serum potassium (and watching for symptoms of low potassium such as muscle weakness, cramps, or palpitations) is the priority when giving furosemide. While keeping an eye on blood pressure and signs of dehydration is also important due to the diuretic effect, the key monitoring focus is potassium to prevent cardiac and muscular complications.