A client on a loop diuretic (furosemide) reports muscle cramps and fatigue. Blood work shows potassium 3.1 mEq/L. Which intervention should the nurse prioritize?

HYPOKALEMIA from loop diuretics:

Normal potassium: 3.5-5.0 mEq/L.

Mild hypokalemia: 3.0-3.4 mEq/L (client's 3.1 mEq/L is mild).

Symptoms: Muscle weakness, cramps, fatigue (matching this client's complaints); SEVERE (<3.0): Potentially fatal cardiac dysrhythmias (PVCs, ventricular fibrillation), severe weakness.

Ecg changes: Flattened T waves, U waves, prolonged QU interval.

Intervention sequence: Notify provider with lab value and symptoms; HOLD furosemide (adding more diuretic increases potassium loss); REPLACE potassium: Oral KCl preferred when tolerated (less dangerous than IV); IV KCl if severe or oral not possible (NEVER IV push — causes cardiac arrest).

Dietary: Bananas, oranges, melons, potatoes, leafy greens, yogurt.

Monitoring: Repeat labs after replacement; cardiac monitoring if K+ <3.0; assess muscle weakness and ECG.

Renal: Ensure adequate renal function before aggressive replacement — hyperkalemia is also dangerous.