Duloxetine-induced syndrome of inappropriate antidiuretic hormone secretion and seizures

Abstract

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) and hyponatremia is a well known side effect of older selective serotonin reuptake inhibitors (SSRIs) such as paroxetine, sertraline, fluoxetine, citalopram, escitalopram, and fluvoxamine.1,2 The frequency of hyponatremia is around 8 per 1,000 among elderly women receiving fluoxetine.2 Although the second-generation dual blockers, selective serotonin–norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine and duloxetine, are touted to have a wider therapeutic index, hyponatremia is encountered even with venlafaxine. To date, Medline searches do not reveal any reports of hyponatremia associated with duloxetine. We describe a woman who developed severe hyponatremia on exposure to duloxetine and recurrence on inadvertent rechallenge, suggesting the causative relationship of this drug to hyponatremia. A 48-year-old woman was hospitalized for acute severe headache and treated with IV fluids and analgesics. Over the next few days, she had multiple aches and pains and …