Syndrome of inappropriate antidiuretic hormone secretion associated with desvenlafaxine.

Objective: To report a case of syndrome of inappropriate anti-diuretic hormone (SIADH) secretion associated with desvenlafaxine.

Methods: A 57-year old female with hyponatraemia. Her medications included desvenlafaxine, and symptoms included nausea, anxiety and confusion. The serum sodium at this time was 120 mmol/L, serum osmolality was 263 mosmol/kg, urine osmolality 410 mosmol/kg and urine sodium 63 mmol/L, consistent with a diagnosis of SIADH. Desvenlafaxine was ceased and fluid restriction implemented. After 4 days the sodium increased to 128 mmol/L and fluid restriction was relaxed. During her further 3 weeks inpatient admission the serum sodium ranged from 134 to 137 mmol/L during treatment with mirtazapine.

Conclusions: SIADH has been widely reported with a range of antidepressants. This case report suggests that desvenlafaxine might cause clinically significant hyponatremia. Conclusions: Clinicians should be aware of the potential for antidepressants to cause hyponatremia,and take appropriate corrective action where necessary.