Behind the Curtain: Therapeutic Drug Monitoring of Psychotropic Drugs from a Laboratory Analytical Perspective

Abstract

Therapeutic drug monitoring (TDM) is a well-established tool for guiding psychopharmacotherapy and improving patient care. Despite their established roles in the prescription of psychotropic drugs, the "behind the curtain" processes of TDM requests are invariably obscure to clinicians, and literature addressing this topic is scarce. Methods:In the present narrative review, we provide a comprehensive overview of the various steps, starting from requesting TDM to interpreting TDM findings, in routine clinical practice. Our goal was to improve clinicians' insights into the numerous factors that may explain the variations in TDM findings due to methodological issues. Results:We discussed challenges throughout the TDM process, starting from the analyte and its major variation forms, through sampling procedures and pre-analytical conditions, time of blood sampling, sample matrices, and collection tubes, to analytical methods, their advantages and shortcomings, and the applied quality procedures. Additionally, we critically reviewed the current and future advances in the TDM of psychotropic drugs. Conclusions:The "behind the curtain" processes enabling TDM involve a multidisciplinary team, which faces numerous challenges in clinical routine. A better understanding of these processes will allow clinicians to join the efforts for achieving higher-quality TDM findings, which will in turn improve treatment effectiveness and safety outcomes of psychotropic agents.

Novel Identification of Cysteinyl Derivatives of Toxic Clozapine Nitrenium Ions and the Effect of Valproic Acid on Metabolite Formation: A Study Using Reprocessed High-Resolution Mass Spectra of Analyzed Therapeutic Drug Monitoring Samples

“…TDM is an important tool for guiding the best possible psychopharmacological treatment for individual patients. 15 TDM data may also be used for research purposes, but this is always associated with methodological limitations, such as information on dose prescription, blood sampling time for TDM, comedications, and organ functions of the patients. However, these limitations are probably outweighed to a large extent by the high number of patients included in TDM databases.…”

Differential expression of Cytochrome P450 1A2 in simple fatty liver and steatohepatitis

“…The CYP1A2 content is approximately 13% of the total CYP amount in the human liver, and 80% homology of CYP1A2 is retained between humans and rats (Martignoni et al, 2006). Human and rat CYP1A2 catalyzes the metabolism of theophylline and the atypical antipsychotic clozapine, which are subjected to therapeutic drug monitoring (TDM) (Guo et al, 2021;Scherf-Clavel et al, 2023). Therefore, even in humans, CYP1A2-catalyzed drug metabolism may be altered during the early stages of NAFL and NASH.…”

Assessing Pharmacokinetic Correlates of Escitalopram-Related Adverse Drug Reactions

“…The use of TDM is part of routine patient monitoring during ESC-based treatment. 23 Furthermore, TDM was performed when indicated for clinical reasons, such as when ADRs occurred or for other common TDM indications (see Table , Supplemental Digital Content 1 , http://links.lww.com/TDM/A718 ). 24 , 25 Data registration followed standardized protocols.…”