SSRI/SNRI -induced Hyponatremia: A Case Series of 26 Patients in a Single Institution from 2018 to 2020.

Antidepressant medications are widely used by patients with depression or a depressive disorder. In spite of a generally favorable safety profile of selective serotonin reuptake inhibitors or serotonin - norepinephrine reuptake inhibitors (SSRI/SNRI), several cases of a possible connection between SSRI/SNRI and hyponatremia have been reported. To describe the clinical characteristics of patients with hyponatremia after SSRI/SNRI exposure, and to examine the association between SSRI/SNRI exposure and the presence of hyponatremia in a Chinese population. A retrospective single-center case series study. We performed a retrospective evaluation of inpatients with SSRI/SNRI-induced hyponatremia from a single institution in China between 2018 and 2020. Clinical data were obtained through review of medical records. Patients who met the initial inclusion criteria but did not develop hyponatremia acted as controls. The study was approved by the Clinical Research Ethics Board of Beijing Hospital (Beijing, P.R. China). We identified 26 patients with SSRI/SNRI-induced hyponatremia. The incidence rate of hyponatremia was 1.34% (26/1937) in the study population. The mean age at diagnosis was 72.58 (±12.84) years, with a male: female ratio of 1:1.42. The duration between SSRI/SNRI exposure and the onset of hyponatremia was 7.65 (±4.88) days. The minimum serum sodium level was 2328.23 (±107.25) mg/dL in the study group. Seventeen patients (65.38%) received sodium supplements. Four patients (15.38%) switched to another antidepressant. Fifteen patients (57.69%) recovered by the time of discharge. There were significant differences in serum potassium, serum magnesium and serum creatinine level between the two groups (p < 0.05). The rate of use of sertraline was significantly higher in the study group compared with the control group (p < 0.05). This pattern was not found in other SSRI/SNRI (p > 0.05). The results of our study show that SSRI/SNRI exposure, in addition to hyponatremia, may also affect the level of serum potassium, serum magnesium and serum creatinine. A history of hyponatremia and exposure to SSRI/SNRI may be potential risk factors for the development of hyponatremia. Future prospective studies are needed to validate these findings.