How does Kayexalate function in the treatment of hyperkalemia?

• A. Stabilizes cardiac membrane
• B. Enables renal excretion of potassium
• C. Shifts potassium into cells
• D. Causes diarrhea to excrete potassium

Answer: (D)

Kayexalate, also known as sodium polystyrene sulfonate, treats hyperkalemia primarily by causing diarrhea, which leads to the excretion of potassium. The mechanism involves the resin binding to potassium ions in the gastrointestinal tract. When Kayexalate is administered, it exchanges sodium for potassium in the gut, resulting in the elimination of potassium from the body through feces. This binding process effectively reduces serum potassium levels, thereby alleviating hyperkalemia.

While it is important to recognize that other treatments for hyperkalemia exist—such as calcium gluconate to stabilize cardiac membranes and insulin or beta-agonists that shift potassium into cells—Kayexalate's distinct action of causing diarrhea is crucial in its specific mechanism of potassium elimination. Thus, the correct function of Kayexalate lies in its ability to facilitate potassium excretion through the gastrointestinal route, leading to decreased potassium levels in patients suffering from hyperkalemia.