What is it about?
Several classes of antidepressants can induce syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH), thereby causing hyponatremia. Initial symptoms of hyponatremia include neuropsychiatric and gastrointestinal manifestations can mimic depression, especially in elderly people with multiple somatic complaints. Here we present a case of a 68-year-old man with treatment-refractory depression and general anxiety disorder who developed duloxetine-induced hyponatremia. His symptoms of hyponatremia including unsteady gait, dizziness, nausea, general malaise, and poor appetite subsided after discontinuing the offending medication. Our case illustrates that drug-induced SIADH and potential drug-drug interactions should be considered in elderly patients who develop hyponatremia following the initiation of antidepressants.
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Why is it important?
Duloxetine and other serotonin-norepinephrine reuptake inhibitors reportedly induce hyponatremia in 5.7% of patients aged 60 or older. Conversely, agomelatine has not been reported to induce hyponatremia. Furthermore, the interactions of drugs with newer antidepressants are insignificant. Large-scale clinical studies evaluating the incidence of hyponatremia in patients utilizing duloxetine are lacking. The initial symptoms of hyponatremia are primarily neuropsychiatric and gastrointestinal disturbances such as dizziness, clouding of consciousness, psychomotor retardation, confusion, gait impairment, falls, seizures, and nausea/vomiting/diarrhea. Some of them can mimic depression especially in elderly patients with multiple somatic complaints. Herein, we describe a case of hyponatremia secondary to syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH) associated with initiation of duloxetine and potentially exacerbated by agomelatine.
Perspectives
I hope this article makes people aware of the unexpected adverse effect while newly prescribing duloxetine to a patient. Hyponatremia is a rare adverse effect of duloxetine; by contrast, agomelatine has not been reported to induce hyponatremia but has a 5-HT2C receptor antagonistic effect and the potential to prolong the half-life of duloxetine. Therefore, caution should be used when prescribing these drugs together given the potential for drug-drug interactions. Patients with risk factors for hyponatremia who are newly initiated on antidepressants should have their sodium levels closely monitored. Once diagnosed with antidepressant-induced SIADH, the potentially offending medications should be stopped immediately, and the patient should undergo a hyponatremia workup.
Ching-Fang Sun
China Medical University
Read the Original
This page is a summary of: Duloxetine-Induced Hyponatremia in an Elderly Male Patient with Treatment-Refractory Major Depressive Disorder, Case Reports in Psychiatry, May 2019, Hindawi Publishing Corporation,
DOI: 10.1155/2019/4109150.
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