[Chronic hyponatremia secondary to drug-induced syndrome of inappropriate antidiuretic hormone secretion - The role of oral urea as a safe and effective therapeutic alternative].

Introduction: hyponatremia is one of the most common electrolyte disturbances in clinical practice. Among the causes of euvolemic hyponatremia, syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most prevalent etiologies, with medications being one of its common triggers. Case report: we present the case of a 71-year-old woman with chronic euvolemic hyponatremia secondary to drug-induced SIADH, in the context of ongoing treatment with multiple potentially implicated medications. Discussion: the significance of this case lies in demonstrating the efficacy and safety of oral urea as a maintenance treatment in a patient for whom discontinuation of the causative medications was not possible due to the need for chronic psychopharmacological treatment. It also illustrates the profile of a patient who is a candidate for treatment with oral urea: chronic euvolemic hyponatremia secondary to SIADH, in which fluid restriction is not feasible, and other therapeutic alternatives presented limitations.