Regarding the direct costs and the social value of depression, the decision of an
antidepressant treatment prescription must be optimized as much as possible. The development
of a personalized medicine in psychiatry may reduce treatment failure, intolerance or
resistance, and hence burden and costs of affective disorders.
There is hope that biomarkers will be found to guide treatment selection. It might be of
decisive interest to be able to assess an individual's metabolism activity. We propose here
to explore the relationship between the activity of drug-metabolizing enzymes (DME) and
transporters- assessed by a phenotypic approach and the efficacy of antidepressants. We will
focus on venlafaxine (V) that provides a reasonable second-step choice for patients with
depression and is used extensively in psychiatric practice, and the metabolism of which
involves several cytochromes (CYP) P450 enzymes and the transporter P-gp.
Thus, the primary objective of this study is to study the correlation between the
concentration of V and its metabolite ODesmethylV (V+ODV) and drug metabolism variability
assessed by a phenotypic approach, in patients with major depressive disorder and MADRS ≥ 20
despite 4 weeks of V at 150mg or less