Which electrolyte-related side effect is associated with hydrochlorothiazide?

• A. Hyperkalemia
• B. Hyponatremia
• C. Hyperglycemia
• D. Leg cramps due to hypokalemia

Answer: (D)

Thiazide diuretics like hydrochlorothiazide disrupt electrolyte handling in the distal nephron, which is the key concept here. By blocking NaCl reabsorption in the distal tubule, they increase the loss of sodium and water. The increased flow and sodium delivery to the collecting duct promote potassium secretion, leading to hypokalemia. Low potassium levels commonly cause muscle cramps, so leg cramps due to hypokalemia is the most direct and recognizable electrolyte-related side effect of hydrochlorothiazide. Hyponatremia or hyperglycemia can occur with thiazides in some patients, and hyperkalemia is not expected, but the cramping from potassium loss best matches the drug’s characteristic effect.