Effects of the augmentation with quetiapine or olanzapine on the metabolism of duloxetine: a retrospective analysis.
Nele Römer, Arnim Johannes Gaebler, Irene Neuner, Ekkehard Haen, Christoph Hiemke, Georgios Schoretsanitis, Michael Paulzen
Author Information
Nele Römer: Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital RWTH Aachen, Aachen, Germany.
Arnim Johannes Gaebler: Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital RWTH Aachen, Aachen, Germany.
Irene Neuner: Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital RWTH Aachen, Aachen, Germany.
Ekkehard Haen: Department of Psychiatry and Psychotherapy, Clinical Pharmacology, University of Regensburg, Regensburg, Germany.
Christoph Hiemke: Department of Psychiatry and Psychotherapy and Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center of Mainz, Mainz, Germany.
Georgios Schoretsanitis: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatry University Hospital Zurich, University of Zurich, Zurich, Switzerland. ORCID
Michael Paulzen: Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital RWTH Aachen, Aachen, Germany. ORCID
BACKGROUND: In antidepressant augmentation strategies, olanzapine or quetiapine are often concomitantly administered to duloxetine. The use of the same enzymes for the degradation of the drugs may lead to clinically relevant drug-drug-interactions, DDIs. So far, DDIs between olanzapine or quetiapine and duloxetine have only been studied in rats or in small numbers of patients. METHODS: Out of a large therapeutic drug monitoring (TDM) database of duloxetine concentrations, three matched study groups were considered to investigate potential DDIs: a group of patients co-medicated with olanzapine ( = 81), a group co-medicated with quetiapine ( = 105) and a control group receiving only duloxetine ( = 105). RESULTS: Neither in the olanzapine group, nor in the quetiapine group, duloxetine plasma concentrations or dose-adjusted plasma concentrations differed significantly from the control group ( = 0.6759; = 0.5841). The proportion of patients within the so-called therapeutic reference range was similar in all three groups ( = 0.635). However, smokers showed by 30% lower duloxetine plasma concentrations ( = 0.0179) and 32.5% lower dose-adjusted concentrations ( = 0.0003) compared to nonsmokers. CONCLUSION: Our findings indicate that the combination of duloxetine and olanzapine or quetiapine is - from a pharmacokinetic view - a safe treatment option. TDM should be applied in case of co-medications to enhance therapeutic effectiveness and patients' safety.
