Syndrome of inappropriate antidiuretic hormone associated with escitalopram therapy

Escitalopram is the selective serotonin reuptake inhibitor (SSRI) most recently approved for use in the United States. It is structurally related to citalopram, but is felt to have a more tolerable side-effect profile than its parent compound. Side effects are not generally serious and include headache, diarrhea, and nausea. While hyponatremia and the syndrome of inappropriate antidiuretic hormone (SIADH) have been associated with treatment with other SSRIs, there has only been one case of escitalopram-induced SIADH reported in the literature to date. We now report another case of a patient who developed SIADH after being treated with escitalopram for 4 weeks. The patient's hyponatremia improved following the discontinuation of escitalopram. Clinicians should be aware of this uncommon but significant side effect of SSRIs and monitor high-risk patients for the development of SIADH.