Syndrome of inappropriate secretion of antidiuretic hormone due to citalopram and venlafaxine.
BACKGROUND
Selective serotonin reuptake inhibitors (SSRIs) and venlafaxine are often used to treat depression in the elderly due to their low incidence of side effects. All five of the SSRIs currently available and venlafaxine have been associated with hyponatremia.


METHODS
This article describes the case of an 87-year-old man with depression who presented with hyponatremia after starting treatment with citalopram. After excluding other common causes of hyponatremia, a diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was confirmed. Sodium levels returned to the normal range following discontinuation of citalopram. Subsequently, due to the persistence of depression, treatment with venlafaxine was initiated. Three weeks later, hyponatremia associated with SIADH was once again diagnosed and venlafaxine was discontinued. The hyponatremia resolved in 2 weeks.


CONCLUSIONS
Both SSRIs and venlafaxine have been associated with SIADH in numerous case reports and retrospective studies. Risk factors for developing hyponatremia with these drugs are advanced age and treatment with other medications. To our knowledge, this is the first case report in which SIADH was associated with two different families of antidepressants in the same patient.


CONCLUSIONS
Physicians should be aware of the risk of hyponatremia when prescribing SSRIs and venlafaxine in elderly patients with multiple drug therapies. Sodium levels should be monitored during treatment.
Romero
Soledad
S
Instituto Clínico de Neurociencias, Hospital Clínico de Barcelona, University of Barcelona, Barcelona 08036, Spain. romeros@upmc.edu
Pintor
Luis
L
Serra
Montserrat
M
Plana
Teresa
T
Navarro
Víctor
V
Gastó
Cristóbal
C
Goldstein
Benjamin
B
D000369:Aged, 80 and over; D015283:Citalopram / Q000009:adverse effects*; D003511:Cyclohexanols / Q000009:adverse effects*; D003865:Major Depressive Disorder / Q000188:drug therapy*; D006801:Humans; D007177:Inappropriate ADH Syndrome / Q000139:chemically induced*; D008297:Male; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects*; D000069470:Venlafaxine Hydrochloride
D015283:Citalopram; D003511:Cyclohexanols; D017367:Selective Serotonin Reuptake Inhibitors; D000069470:Venlafaxine Hydrochloride