Which electrolyte disturbance is typically seen with loop diuretics?

• A. Hyperkalemia
• B. Hypermagnesemia
• C. Hypokalemia and hypomagnesemia
• D. Hypokalemia only

Answer: (C)

Loop diuretics block the Na-K-2Cl transporter in the thick ascending limb, which increases sodium delivery to the distal nephron. To balance the extra positive charge, potassium is secreted into the lumen and magnesium reabsorption in the TAL is reduced, leading to losses of both potassium and magnesium. That combination—low potassium with low magnesium—is a characteristic electrolyte disturbance with loop diuretics.

Hyperkalemia would not fit because these drugs promote potassium loss, not retention. Hypermagnesemia is unlikely because magnesium is also wasted rather than conserved. Only stating hypokalemia misses the common magnesium loss, making the combined hypokalemia and hypomagnesemia the best description.