[Determining serum concentrations of the modern antipsychotic quetiapin: clinical relevance in therapeutic drug monitoring].

Objective: The results concerning therapeutic drug monitoring of Quetiapin concentration in 152 in-patients will be presented.
Method: In addition to measuring the serum concentration of Quetiapin standardized patient data were collected and the clinical history assessed by the Brief Psychiatric Rating Scale (BPRS).
Results: A significant positive correlation of the serum concentration and the daily dosage was found. Co-medication with the CYP 3A4 inhibitor Nefazodon was associated with an increase in the serum concentration without any adverse interactions occurring.
Conclusion: While a correlation of dosage and effect could be shown with Quetiapin, inter- and intraindividual differences could be observed. Drug monitoring therefore seems useful in clinical setting and is recommended.