Which therapy lowers potassium by shifting it into cells?

• A. Insulin + glucose
• B. Calcium gluconate
• C. Kayexalate
• D. Dialysis

Answer: (A)

Shifting potassium into cells is a fast way to reduce the dangerous high level in the blood. Insulin activates the Na+/K+ ATPase pump, pulling potassium from the extracellular space into cells. When given with glucose, it prevents hypoglycemia and reliably lowers serum potassium within minutes to an hour, which is crucial in acute hyperkalemia, especially if there are ECG changes.

Calcium gluconate doesn’t lower potassium; it stabilizes cardiac membranes so the heart is less vulnerable to the effects of high potassium while the levels remain high. Kayexalate binds potassium in the gut to enhance its elimination, but this is slower and doesn’t move potassium into cells. Dialysis removes potassium directly from the blood, again not by shifting it into cells but by physical removal, and is used when rapid elimination is needed or in kidney failure. So the option that lowers potassium by shifting it into cells is insulin with glucose.