Citalopram-Related SIADH

Abstract

Objective: To report a case of syndrome of inappropriate antidiuretic hormone (SIADH) after the initiation of citalopram and trazodone therapy. Case Summary: A 75-year-old white woman developed SIADH after the initiation of citalopram and trazodone therapy. Discussion: Selective serotonin-reuptake inhibitors (SSRIs) and trazodone have been associated with hyponatremia in the literature. There are numerous reports of SSRIs, primarily fluoxetine, associated with SIADH. There are 8 case reports of SIADH reported with citalopram in the literature, which were identified through a MEDLINE search that included all languages and bibliographic review of those cases. The number of citalopram cases may not be associated with a reduced incidence but with the infrequency of citalopram use compared with the widespread use of fluoxetine. The mechanism of action of citalopram is enhancement of serotoninergic neurotransmission, which is similar to other serotonin (5-HT) reuptake inhibitors. To date, there are only 2 reports of trazodone associated with hyponatremia in the literature, both as a result of an overdose. Conclusions: SIADH has been reported with several SSRIs, but to a lesser degree with citalopram, which may be attributed to the lower number of patients using it compared with other SSRIs. Increased awareness and monitoring of SIADH is important, especially in older patients who may be at an increased risk of SIADH.