The electrolyte change commonly associated with beta-2 agonist therapy is which?

• A. Hyperkalemia
• B. Hyponatremia
• C. Hypokalemia
• D. Hypocalcemia

Answer: (C)

Beta-2 agonists stimulate receptors that increase cellular uptake of potassium by driving potassium into cells via the Na+/K+-ATPase pump. This shifts potassium from the bloodstream into tissues, lowering serum potassium levels, so hypokalemia is the electrolyte change most commonly seen with beta-2 agonist therapy. This effect is usually mild but can be clinically important in patients with low potassium or on diuretics and may contribute to arrhythmias in some situations.

Hyperkalemia would not fit because it implies potassium staying outside cells or being released from cells, which beta-2 agonists do not promote. Hyponatremia and hypocalcemia are not typical effects of beta-2 agonist therapy.