Sertraline-induced hyponatremia

A 53-year-old female patient with a history of carcinoma of the breast in remission and dilated cardiomyopathy on treatment was newly diagnosed with depression. She was started on sertraline 50 mg once a day. 2 days later she developed severe hyponatremia (serum sodium 114 mEq/l). Her condition further deteriorated and on the 6^th day her medication was stopped and replaced with mirtazapine. Osmolality studies she was diagnosed with syndrome of inappropriate antidiuretic hormone secretion. She was treated with IV sodium chloride for her hyponatremia. At discharge serum sodium levels improved (127 mEq/l) and subsequent follow-up 4 weeks later showed normal sodium values (138 mEq/L).