What is the first-line therapy for hyperkalemic emergencies?

• A. Furosemide
• B. Hemodialysis
• C. Calcium gluconate
• D. Regular insulin with dextrose

Answer: (C)

The key idea is to stabilize the heart immediately when potassium is dangerously high. Calcium gluconate is given intravenously to protect the cardiac membranes, reducing the risk of life-threatening arrhythmias. This stabilization happens quickly, buying time for other treatments that actually lower or remove potassium to take effect. Calcium does not lower potassium itself; it simply keeps the heart safe while you use other therapies.

After the heart is stabilized, you shift potassium into cells (for example with insulin and glucose, or beta-agonists, and sometimes bicarbonate if indicated) or remove it from the body (via diuretics if kidney function allows, cation-exchange resins, or dialysis). The other options don’t provide that immediate membrane stabilization: they either act more slowly, depend on kidney function, or address potassium levels rather than protecting the heart in the emergency moment.