How should potassium be replaced in a patient with hypokalemia and a non-emergent IV access, and why is rapid infusion dangerous?

• A. IV potassium chloride should be infused no faster than 10 mEq/hour; rapid infusion can cause life-threatening arrhythmias and tissue injury
• B. IV potassium chloride can be infused at 50 mEq/hour
• C. Oral potassium is always preferred
• D. Never give potassium IV

Answer: (A)

Potassium replacement must be done slowly because it directly affects the heart’s electrical activity. In a patient with hypokalemia who has non-emergent IV access, giving potassium chloride through a vein at a controlled, slow rate is essential to prevent dangerous shifts in potassium that can destabilize cardiac conduction. If potassium is infused too quickly, the extracellular potassium can rise rapidly, increasing the risk of life‑threatening arrhythmias such as ventricular tachycardia or fibrillation, and it can also cause tissue injury at the IV site if there’s extravasation. For non-emergent correction, a safe upper limit is about 10 mEq per hour, with the solution properly diluted and the patient monitored (ECG, urine output, and serial potassium checks). Oral potassium can be preferred when the patient can take it, but when IV replacement is used, keeping the rate at or below 10 mEq/hour minimizes the dangers of rapid infusion.