Utility of therapeutic drug monitoring in the treatment of major depressive disorder.

PURPOSE OF THE NARRATIVE REVIEW: Response and remission rates in patients with major depressive disorder (MDD) treated with antidepressants are frequently not satisfying. Therapeutic drug monitoring (TDM), i.e. the quantification of antidepressant drug levels in blood and dose adjustment, is a modern and useful tool of personalized pharmacological treatment of MDD.

RECENT FINDINGS: Emerging evidence suggests that the use of TDM for antidepressants can be helpful in numerous clinical scenarios. Such scenarios include lack of treatment response, relapse, or adverse drug reactions related to antidepressants. The use of TDM is also indicated in specific patient subgroups, such as children, adolescents, pregnant women, elderly patients and patients with intellectual disabilities. Patients with polypharmacy and/or physical comorbidities may also benefit from TDM-guided antidepressant treatment. We critically reviewed TDM literature on antidepressants, summarizing therapeutic reference ranges and laboratory alert levels for antidepressants, although TDM is not equally recommended/supported for all antidepressants.

SUMMARY: The utilization of TDM as a tool for treatment optimization in clinical routine with antidepressants for patients with MDD offers a valuable method to improve safety and effectiveness. This work summarizes essential TDM knowledge for antidepressants and encourages the application of TDM as part of the clinical decision-making process.