Sorbitol-induced hypokalemia is caused by which mechanism?

• A. Inadequate dietary intake
• B. Increased renal potassium loss
• C. Excess potassium loss in the stool
• D. Transcellular shift of potassium into cells

Answer: (C)

Sorbitol acts as an osmotic laxative, triggering diarrhea that carries potassium out of the body in the stool. The substantial GI potassium losses from this stool output are what drive hypokalemia, making excess potassium loss in the stool the best explanation. Inadequate dietary intake doesn’t explain an acute drop, sorbitol doesn’t primarily cause increased renal potassium loss, and there isn’t a transcellular shift of potassium into cells triggered by sorbitol.