Hyponatremia Associated with Paroxetine

Hyponatremia is an uncommon but widely reported complication of selective serotonin uptake inhibitors (SSRIs), and most of the case reports involve elderly patients. The presentation is usually that of SIADH, but the underlying mechanism leading to the syndrome is poorly understood. Since the use of SSRIs is becoming more popular among elderly depressed patients and because of the potentially serious consequence of hyponatremia, psychiatrists should be alert to the development of the complication and familiarize themselves with its diagnosis and treatment. We report two elderly patients who were identified to have hyponatremia after the commencement of paroxetine. This illustrates the need for monitoring of plasma sodium level if a patient's clinical condition deteriorates. Other factors possibly related to the hyponatremia are discussed and a review of the diagnosis and management of SSRI-related hyponatremia is included.