Pharmacopsychiatry 2003; 36 - 46
DOI: 10.1055/s-2003-825297

Relevance of therapeutic drug monitoring (TDM) in patients with quetiapine administration

D Degner 1, B Bandelow 1, R Akkan 1, S Kropp 2, PD Nietmann 3, E Rüther 1, S Bleich 4
  • 1Department of Psychiatry and Psychotherapy, University of Göttingen, Germany
  • 2Department of Psychiatry, Medical School, Hannover, Germany
  • 3Department of Clinical Chemistry, University of Göttingen, Germany
  • 4Department of Psychiatry and Psychotherapy, University of Erlangen, Germany

Introduction: Quetiapine is a new atypical antipsychotic agent,the relevance of TDM is still discussed.

Method: 83 patients from the Department of Psychiatry, University of Göttingen, Germany,were investigated.Quetiapine plasma concentrations were analyzed using reversed phase HPLC with ultraviolet detection.

Results: 83 patients (f: 47, m: 36, aged 19–79 y, mean:45.8 y) with totally 341 plasma samples were examined.Quetiapine dosages ranged between 25 to 1200mg/d ,mean: 371.6mg/d (plasma concentrations 5 to 1312,mean:139.4 ng/ml). There was no significant correlation between dosages and plasma levels. Relevant factors were age of patients and mono vs. combination treatments.

Conclusion: TDM is an useful element in optimizing antipsychotic therapy (compliance,drug combinations, adverse reactions). Once of the limitations is the short elimination half-life of quetiapine (CYP3A4 metabolism). The results are similar to possible therapeutic ranges (40–170 ng/ml) documented in other studies[1]. 1) Small JG. Arch Gen Psychiatry 1997; 54: 253–273