Mirtazapine Plasma Levels: Application of a Modified Target Concentration Intervention (TCI)

Target concentration intervention (TCI) represents a method for optimizing pharmacological therapy that differs from therapeutic drug monitoring (TDM) by the determination of target plasma levels. The therapeutic range (TDM) is replaced by individually ascertained plasma concentrations (TCI) reflecting both optimal clinical effectiveness and maximum tolerability (Holford 2003).

In a naturalistic study 34 in-patients suffering from depressive disorders (according to ICD-10 diagnostic criteria) were investigated. The patients received the antidepressant mirtazapine (NaSSa) which selectively acts on noradrenergic-serotonergic system and for which a rapid onset of the desired effects is described. The hypothesis whether a better therapeutic effect was achived by utilizing a modified TCI was examined. By means of the HPLC method mirtazapine plasma levels were determined at different times. In the laboratory patients were randomly distributed to a group with and one without TCI, whereby the patients with TCI were assigned a plasma level range of 40 ng/ml. Mirtazapine was dispensed according to laboratory recommendations (with TCI) or by clinical assessment (without TCI). The severity of the depressive symptoms was recorded at the beginning and during the course of the observation with the Hamilton Depression scale (HAMD-21) and the final assessment was concluded with clinical global impression (CGI).

The results are presented in the workshop.