INCIDENCE OF SELECTIVE SEROTONIN REUPTAKE INHIBITOR (SSRI) INDUCED HYPONATREMIA DUE TO THE SYNDROME OF INAPPROPRIATE ANTIDIURETIC-HORMONE (SIADH) SECRETION IN THE ELDERLY

Objective. The study determines the incidence of SSRI-induced hyponatr aemia due to SIADH in an elderly psychiatric inpatient population. Des ign. A retrospective case-note study. Setting. An acute old age psychi atry ward, Sample. Patients admitted from January 1 to December 31, 19 96. Measures. Demographics, medication, psychiatric diagnoses, plasma sodium level and physical comorbidity were collected, Patients on SSRI s were selected and those developing hyponatraemia due to SIADH were i dentified. Results. Of 32 patients taking SSRIs, four developed sympto matic hyponatraemia due to SIADH (12.5%), A further four developed asy mptomatic hyponatraemia following introduction of an SSRI (12.5%), alt hough laboratory confirmation of SIADH was lacking, Conclusions. The i ncidence of SSRI-induced hyponatraemia due to SIADH has not previously been established. This study shows a high incidence in elderly patien ts of this potentially dangerous complication. Clinical practice in th e prescription of SSRIs to elderly people must change to include monit oring of electrolytes for early detection and reduction of morbidity. (C) 1998 John Wiley & Sons, Ltd.