A nurse is reviewing the medical record of a client and identifies a serum potassium 6.8 mEq/L (3.5-5 mEq/L). Which of the following medications should the nurse expect to administer?

A. Acetylcysteine is used as a mucolytic or as an antidote for acetaminophen toxicity and has no effect on potassium levels. B. Sodium polystyrene sulfonate (Kayexalate) is used to treat hyperkalemia. It works by exchanging sodium for potassium in the intestines, allowing potassium to be excreted in the stool and lowering serum potassium levels. This is the appropriate medication for a critically elevated potassium level like 6.8 mEq/L. C. Lactulose is used to treat constipation and hepatic encephalopathy; it does not significantly affect serum potassium. D. Triamterene is a potassium-sparing diuretic and would increase potassium levels, making it inappropriate for treating hyperkalemia.