After stabilizing the myocardium with IV calcium in hyperkalemia, which therapy lowers serum potassium rapidly?

• A. Sodium bicarbonate
• B. Insulin with glucose
• C. Diuretics
• D. Hemodialysis

Answer: (B)

Shifting potassium into cells with insulin and glucose is the fastest way to lower serum potassium after calcium has stabilized the myocardium. Insulin stimulates the Na+/K+-ATPase pump, pushing potassium from the extracellular space into cells, which lowers the serum level within minutes to an hour. Glucose is given with insulin to prevent hypoglycemia. Diuretics and dialysis remove potassium by different mechanisms but are not as rapid in many settings (diuretics depend on kidney function and dialysis is used for severe or refractory cases). Bicarbonate can help if there is acidosis, but its effect on potassium is less predictable and slower than insulin with glucose.