title: Hyponatraemia: an audit of aged psychiatry patients taking SSRIs and SNRIs.
abstract: OBJECTIVE
  Hyponatraemia is a serious adverse event commonly reported in elderly people treated with serotonergic antidepressants. The mechanism, incidence and risk factors for antidepressant induced hyponatraemia are not fully understood.
  
  
  METHODS
  In a retrospective chart analysis, depressed patients aged >63 years were investigated for change in serum sodium levels between two time points, separated by a median period of 45.5 days, with the first specimen taken prior to treatment. Patients were grouped into three cohorts; treated with an SSRI or SNRI (n=77), treated with an antidepressant other than an SSRI or SNRI (n=54) and not treated with an antidepressant (n=128).
  
  
  RESULTS
  For change in sodium level between measurements and total number of patients with hyponatraemia, there was no significant difference between cohorts. However, the rate of reduction of serum sodium levels between time points was significantly greater for SSRI and SNRI treated patients (p<0.001) and patients treated with other antidepressants (p=0.03) compared to patients not treated with antidepressants. Moreover, the distribution of values of change in serum sodium was skewed towards reduced serum sodium in patients treated with SSRI or SNRIs (skew -0.43) and patients treated with other antidepressants (skew -0.09) but not for patients without antidepressants (skew 0.25).
  
  
  CONCLUSIONS
  These data suggest that antidepressant treatment is associated with hyponatraemia affecting a subgroup of individuals only. Generalised linear modelling showed that the risk of hyponatraemia increases with increased age, female gender, and particularly the antidepressant agents sertraline and escitalopram. The findings are of clinical significance as they demonstrate that hyponatraemia can occur rapidly with antidepressants, and SSRI/SNRI medications induce more rapid changes. They support the use of electrolyte monitoring early in antidepressant treatment in patients receiving antidepressants.
authors.affiliation: Department of Psychiatry, Melbourne University, Parkville, VIC, Australia. frank@giorlando.org
authors.forename: Francesco
authors.initials: F
authors.lastname: Giorlando
authors.forename: Julia
authors.initials: J
authors.lastname: Teister
authors.forename: Seetal
authors.initials: S
authors.lastname: Dodd
authors.forename: Marc
authors.initials: M
authors.lastname: Udina
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
mesh_terms: D018759:Adrenergic Uptake Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000928:Antidepressive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D015331:Cohort Studies; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000139:chemically induced* / Q000453:epidemiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D012737:Sex Factors; D012964:Sodium / Q000097:blood; D013997:Time Factors
chemical_list: D018759:Adrenergic Uptake Inhibitors; D000928:Antidepressive Agents; D017367:Selective Serotonin Reuptake Inhibitors; D012964:Sodium