Hyponatremia associated with paroxetine induced by sodium-restricted diet and hypotonic saline

An 89-year-old woman taking paroxetine was admitted to our hospital for femoral neck fracture; her diet became sodium restricted due to hypertension. After admission, the femoral head replacement was performed and hypotonic saline was administered over 2 days. On the fifth day after the operation, severe hyponatremia was observed and treated with oral fluid restriction, furosemide, sodium chloride and paroxetine discontinuance. In a few days, serum sodium concentration returned to baseline level.

Besides risk factors for SIADH, a sodium-restricted diet and infusions of hypotonic saline in the perioperative period should be considered risk factors for SIADH associated with paroxetine.