Therapeutic drug monitoring of selective serotonin reuptake inhibitors influences clinical dosing strategies and reduces drug costs in depressed elderly patients

This study was initiated in order to describe and evaluate the effects of a therapeutic drug monitoring (TDM) routine of selective serotonin reuptake inhibitors (SSRIs) on treatment strategies and drug costs in depressed elderly patients.Blood samples were drawn from elderly depressed patients and analysed for steady-state trough serum concentrations of citalopram (n = 48), paroxetine (n = 48) or sertraline (n = 39). A global efficacy evaluation was made at baseline and after 6-9 months. Antidepressant drug costs before and after TDM were estimated.Eight samples were excluded due to technical problems or noncompliance. In 65 of the 127 (51.2%) remaining cases, the treatment strategy was changed according to the TDM outcome, in most a reduction of the prescribed dose. Bioanalytical TDM costs included the antidepressant drug costs after TDM were reduced by 10.2%.The results support the utility of TDM in the search for the individual minimum effective SSRI dose in the elderly.