Association between serum sodium levels and selective serotonin reuptake inhibitors in patients with depression

Abstract

Background: Hyponatremia is known to occur in patients on antidepressants. It is prevalent in approximately 2.5% of general hospital inpatient population, but can approach 11% among elderly patients. Relying only on symptoms for detecting hyponatremia may lead to under-diagnosing of hyponatremia; therefore, routine and frequent testing for serum sodium level is recommended, especially for older patients. This study is done to analyse the association between serum sodium levels and SSRIs in patients with depression. Methods: A Prospective, Interventional study in the in-patient and out-patient department of Psychiatry Department was conducted for 3 months (August 2105 to October 2015). A total of 100 patients, aged over 18 years, diagnosed of depression, on SSRIs were analysed. Changes in serum sodium levels were observed at baseline and Week 4 of starting SSRI. Results: A total of 100 patients were analyzed. 8 patients had serum sodium ≤130mmol-1, out of which 5 were females (62.5%) and 3 were males (37.5%). Prevalence of hyponatremia was more pronounced in patients aged >60 years (100%), on Fluoxetine or Sertraline. Patients between15 to 45 years of age did not experience any clinically significant hyponatremia at the fourth week after the therapy. Conclusions: Our study indicates that users of SSRIs in elderly age group have a higher risk of developing hyponatremia. Clinicians evaluating elderly patients taking SSRIs are encouraged to monitor serum sodium if the patient presents with vague, nonspecific symptoms commonly associated with older age or depression to rule-out SIADH.