Introduction
ADVERSE EFFECTS
Pharmacogenetics has the potential to personalize antidepressant treatment, yet implementation in psychiatry is still very limited.Antidepressants are metabolized by various isoforms of cytochrome P450 (CYP450) enzymes, notably the CYP450 2D6 (CYP2D6) and CYP450 2C19 (CYP2C19) isozymes.Currently, several guidelines are available for optimizing pharmacotherapy by pharmacogenetic testing, among which the guidelines by the Dutch Pharmacogenetics Working Group (DPWG) and the Clinical Pharmacogenetics Implementation Consortium are internationally well recognized.In the present study, we aimed to examine whether dosing based on pharmacogenetics according to the DPWG guidelines resulted in faster attainment of therapeutic TCA plasma concentrations compared with usual treatment. Furthermore, we investigated whether faster attainment of therapeutic concentrations was associated with higher effectiveness and fewer and less severe adverse effects. We hypothesized that application of the DPWG guidelines would result in faster attainment of therapeutic plasma concentrations, higher effectiveness, and a lower rate of adverse effects.