Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 3 1 2018 07 24 10 13 EN Pantea Arya Department of Psychiatry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Sara Hashempour Department of Psychiatry, School of Medicine AND Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran. Akbar Shafiee Department of Community Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Azita Kheiltash Department of Community Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Padideh Ghaeli Department of Psychiatry, School of Medicine AND Roozbeh Hospital AND School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. 2018 01 11 2018 05 23 Hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) occurs as a rare but clinically important phenomena in various conditions including malignant neoplasms, infections, and central nervous system disorders, and as an adverse effect of numerous drugs. To the authors’ knowledge, there are a few reports on SIADH associated with quetiapine in the literature. This case presents a 58-year-old woman receiving quetiapine for the treatment of bipolar disorder. The patient was hospitalized due to generalized tonic-colonic seizure. After checking her laboratory tests, she was found to be hyponatremic, and the treatment began accordingly. The situation was resolved after discontinuation of quetiapine therapy. Quetiapine was thought to be the cause for the patient’s symptoms, and she was diagnosed with SIADH induced by this medication. Close monitoring of the sodium level is recommended in patients taking quetiapine. https://crcp.tums.ac.ir/index.php/crcp/article/view/171 https://crcp.tums.ac.ir/index.php/crcp/article/download/171/99