Systematic TDM of antidepressants in psychiatric inpatients under naturalistic conditions

TDM has been proven a useful tool for tailoring the dosage of tricyclic antidepressants. A large multicenter study has been carried out with the aim of proving also the benefits of TDM of newer antidepressants under naturalistic clinical conditions. 153 psychiatric inpatients with a depressive episode (ICD-10) were included in this investigation. They were randomised into two groups with TDM (n=80) and without TDM (n=73), respectively. Weekly, patients were examined by standardized rating scales (HAMD-17, CGI, UKU) and blood samples were taken for plasma level determinations. The majority of patients were treated with citalopram. There was no statistically significant difference between the two groups with and without TDM for the baseline characteristics of the subjects. Patients improved significantly during treatment with a mean HAMD score of 24at baseline and 14at the endpoint of the study after 7 weeks, respectively (p<0,0005). Comparison of the two groups regarding improvement (reduction of HAMD >20%) and response (reduction of HAMD >50%) revealed a higher percentage of both improvers and responders in the TDM group, even though the level of statistical significance was not reached. These data are preliminary. Currently, a more detailed analysis is under way to explore how TDM was actually used in this study, especially if dosing recommendations were followed by the ordering physicians.