The Syndrome of Inappropriate Secretion of Antidiuretic Hormone and Hyponatremia due to Sodium Valproate Treatment; A Case Report and Review of the Literature

Hyponatremia is defined as a serum sodium level of <135 mEq/l, and it is an important clinical entity that increases mortality and morbidity when not treated. Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is the most common cause of the normovolemic hyponatremia. SIADH may occur in a variety of clinical entity and also as an adverse effect secondary to many drugs. Sodium valproate, an agent widely used for the treatment of schizoaffective disorder, bipolar disorder and epilepsy, rarely cause SIADH and hyponatremia as an adverse effect. The mechanism of sodium valproate associated SIADH and hyponatremia is not exactly known. We aimed to present a case of hyponatremia and SIADH due to repeated use of sodium-valproate and to review the relevant literature.