[Adverse effects of selective serotonin uptake inhibitors. Hyponatremia caused by Schwartz-Bartter syndrome]

This report describes three cases of hyponatraemia/syndrome of inappropriate secretion of antidiuretic hormone. The cases are most likely caused by treatment/intoxication with three different selective serotonin reuptake inhibitors: Fluoxetine, paroxetine and citalopram. All three patients were elderly women (75-83 years). Serum sodium values returned to normal or near normal after discontinuation of the drug and concomitant fluid restriction. Hyponatraemia has previously been described as an adverse effect to fluoxetine and paroxetine, but not to citalopram.