Therapeutic Drug Monitoring

PURPOSE: 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...

BACKGROUND: A patient, with a mental disorder caused by an intracranial infection, treated with olanzapine, fluvoxamine, and buspirone. The plasma exposure of olanzapine was too high at standard doses, with evidence indicating that it was caused by drug-drug interactions. METHODS: Using pharmacogenomics and therapeutic drug monitoring to guide drug dose adjustment for a patient in clinical practice. RESULTS: The patient underwent pharmacogenetic testing in addition to therapeutic drug monitoring as part of a pharmacist-led comprehensive evaluation of medication therapy management in a clinical setting, resulting in improved clinical efficacy that allowed discharge from a psychiatric hospital...

BACKGROUND: Recent studies have reported ethnic differences in vincristine exposure and outcomes such as toxicity. This resulted in the hypothesis of subtherapeutic dosing in African children. To optimize individual treatment, a strategy to identify subtherapeutic exposure using therapeutic drug monitoring is essential. The aim of the current study was to develop a strategy for therapeutic drug monitoring of vincristine in African children to meet the following criteria: (1) identify patients with low vincristine exposure with sufficient sensitivity (>70%), (2) determine vincristine exposure with a limited sampling strategy design of 3 samples, and (3) allow all samples to be collected within 4 hours after administration...

BACKGROUND: In recent years, multiple population pharmacokinetic models have been developed for drugs such as tobramycin that need therapeutic drug monitoring. Some of these models have been used to develop a priori dosing regimens for their respective populations. However, these dosing regimens may not apply to other populations. Therefore, this study aimed to evaluate tobramycin population pharmacokinetic models in critically ill patients and establish an adequate dosing regimen. METHODS: Evaluated models were identified from a literature review of aminoglycoside population pharmacokinetic models in critically ill patients...

BACKGROUND: Cisplatin, widely used in the treatment of solid tumors, causes permanent hearing loss in more than 60% of treated children. Previous studies have implicated several clinical factors in the development of ototoxicity, including cumulative cisplatin dose. However, the role of cisplatin dose intensity in the development of hearing loss in children remains unclear. Pharmacogenetic studies have also identified genetic variants in TPMT that increase the risk of cisplatin-induced hearing loss...

METHODS: A novel microsampling device called Volumetric Absorptive microsampling (VAMS), developed in 2014, appears to have resolved the sample inhomogeneity inherent to dried blood spots, with improved precision in the volume of sample collected for measuring drug concentration. A literature search was conducted to identify several analytical and pharmacokinetic studies that have used VAMS in recent years. RESULTS: The key factors for proper experimental design and optimization of the extraction of drugs and metabolites of interest from the device were summarized...

BACKGROUND: Intravenous high-dose methotrexate (MTX ≥ 1 g/m2) is frequently used in patients with cerebral lymphoma or other malignancies. In addition to its potent efficacy, it is known to have pronounced toxicity and life-threatening side effects. Regular-level monitoring at short and defined intervals is mandatory. This study aimed to evaluate the possibility of replacing peripheral blood sampling with blood samples from central venous catheters for therapeutic monitoring of MTX in adults...

BACKGROUND: Amisulpride, a second-generation atypical antipsychotic drug, was first marketed in Europe in the 1990s. This study aimed to provide a reference for the clinical application of amisulpride. The effects of age, sex, or specific comedications on amisulpride concentrations in Chinese patients with schizophrenia in the real world were investigated. METHODS: A retrospective study was conducted of data on amisulpride based on the therapeutic drug monitoring service database at the Zigong Affiliated Hospital of Southwest Medical University...

BACKGROUND: Therapeutic drug monitoring of mesalazine (5-ASA) in patients with ulcerative colitis is unavailable. Mucosal 5-ASA concentrations are assumed to be higher during remission, but biopsy is not practical. Therefore, we investigated the feasibility of measuring mesalazine levels in feces. To explore the potential role of fecal mesalazine measurements in therapeutic drug monitoring, we compared the dry fecal concentration and daily fecal excretion of 5-ASA and its metabolite N-acetyl-5-ASA in patients with ulcerative colitis with active and quiescent disease...

BACKGROUND: The Immunosuppressant Bayesian Dose Adjustment web site aids clinicians and pharmacologists involved in the care of transplant recipients; it proposes dose adjustments based on the estimated area under the concentration-time curve (AUCs). Three concentrations (T20 min, T1 h, and T3 h) are sufficient to estimate mycophenolic acid (MPA) AUC0-12 h in pediatric kidney transplant recipients. This study investigates mycophenolate mofetil (MMF) doses and MPA AUC values in pediatric kidney transplant recipients, and target exposure attainment when the proposed doses were followed, through a large-scale analysis of the data set collated since the inception of the Immunosuppressant Bayesian Dose Adjustment web site...

BACKGROUND: Vedolizumab (VDZ) is an anti-α4β7 integrin monoclonal antibody approved for inflammatory bowel disease treatment. VDZ serum and antidrug antibody (ADA) concentrations may be used for treatment optimization. In this article, the results of 5 commercial assays (Grifols, Immundiagnostik, Progenika, Sanquin, and Theradiag) measuring VDZ concentration and ADA were compared with those of the reference assays used in VDZ clinical studies. Our findings will assist clinicians in interpreting commercial assay results in the context of VDZ clinical trial data...

BACKGROUND: Therapeutic drug monitoring (TDM) and model-informed precision dosing (MIPD) have greatly benefitted from computational and mathematical advances over the past 60 years. Furthermore, the use of artificial intelligence (AI) and machine learning (ML) approaches for supporting clinical research and support is increasing. However, AI and ML applications for precision dosing have been evaluated only recently. Given the capability of ML to handle multidimensional data, such as from electronic health records, opportunities for AI and ML applications to facilitate TDM and MIPD may be advantageous...

PURPOSE: Vancomycin dosing remains challenging in patients receiving intermittent hemodialysis, especially in developing countries, where access to therapeutic drug monitoring and model-based dose adjustment services is limited. The objectives of this study were to describe vancomycin population PK in patients receiving hemodialysis in a Malian and French center and examine the optimal loading dose of vancomycin in this setting. METHODS: Population pharmacokinetic analysis was conducted using Pmetrics in 31 Malian and 27 French hemodialysis patients, having a total of 309 vancomycin plasma concentrations...

BACKGROUND: Dried blood spot (DBS) sampling is a convenient alternative to whole-blood sampling for therapeutic drug monitoring (TDM) in clinical practice. The aim of this study was to systematically review studies that have examined and used DBS sampling for the TDM of chemotherapy and targeted therapy agents for the treatment of patients with solid cancers. METHODS: Using the PRISMA guidelines, a systematic literature search of EMBASE and PUBMED was performed to identify eligible clinical studies that used DBS sampling to monitor chemotherapy or targeted therapy for the treatment of solid cancers...

PURPOSE: Although designer benzodiazepines (DBZDs) constitute a minor part of new psychoactive substances, they deserve the greatest attention because of their popularity among drug users and increasing number and availability. This review covers the effects of different DBZDs, available pharmacological evaluation tools, and their reported toxicity and potential pharmacodynamic and pharmacokinetic interactions with other drugs commonly co-abused with DBZDs. METHODS: For this narrative review, a nonsystematic search was performed on PubMed, EMBASE, Google Scholar, and PubMed Central databases between June and July 2021...

BACKGROUND: Bisphenol A (BPA) is a ubiquitous contaminant that has endocrine-disrupting effects. Chlorinated derivatives of BPA are formed during chlorination of drinking water and have higher endocrine-disrupting activity. Dichlorobisphenol A (Cl2BPA) is the most abundant chlorinated BPA derivative found in several human biological matrices. Recent in vitro experiments have shown that Cl2BPA is metabolized in sulpho- and glucuro-conjugated compounds. To date, no assay has been developed to quantify the sulfo- and glucuro-conjugates of 3,3'-Cl2BPA (3,3'-Cl2BPA-S and 3,3'-Cl2BPA-G, respectively)...

BACKGROUND: Fexofenadine is a recommended in vivo probe drug for phenotyping P-glycoprotein (P-gp) and organic anion transporting polypeptide (OATP) 1B1/3 transporter activities. This study evaluated a limited sampling strategy using a population pharmacokinetic approach to estimate plasma fexofenadine exposure as an index of P-gp and OATP activities. METHODS: In a previous study, a single oral dose of fexofenadine (120 mg) was administered alone or in combination with grapefruit juice, Panax ginseng, or Echinacea purpurea to healthy adult participants...

BACKGROUND: Perampanel (PER) is an oral antiepileptic drug and its concomitant use with carbamazepine (CBZ) leads to decreased PER concentrations. However, the magnitude of its influence may vary, depending on the dynamics of the enzyme induction properties of CBZ. This study aimed to develop a population pharmacokinetic (PPK) model considering the dynamics of enzyme induction and evaluate the effect of CBZ on PER pharmacokinetics. METHODS: We retrospectively collected data on patient background, laboratory tests, and prescribed drugs from electronic medical records...

BACKGROUND: Anthracyclines, which are effective chemotherapeutic agents, cause cardiac dysfunction in up to 57% of patients. The cumulative anthracycline dose is a crucial predictor of cardiotoxicity; however, the cumulative dose alone cannot explain all cardiotoxic events. Strongly associated genetic variants in SLC28A3, UGT1A6, and RARG contribute to anthracycline-induced cardiotoxicity in pediatric patients and may help identify those most susceptible. This study aimed to examine how these pharmacogenetic effects are modulated by cumulative anthracycline doses in the development of cardiotoxicity...

BACKGROUND: Therapeutic drug monitoring (TDM) of poly(ADP-ribose) polymerase inhibitors (PARPis) is an exploratory practice aimed at improving the quality of treatment through personalized therapy. Currently, there are 4 European Medicines Agency-approved and US Food and Drug Administration-approved PARPis available clinically whose quantification requires validated analytical methods: olaparib, niraparib, rucaparib, and talazoparib. The purpose of this literature review was to highlight the pharmacological features of PARPis that could support their TDM practice and provide a detailed discussion of the available liquid chromatography coupled with tandem mass spectrometry methods for their quantification...