The Impact of Once Daily Dosing on Protein Binding of Clozapine and Norclozapine.

Purpose/background: Clozapine and norclozapine are highly protein bound. Currently, clozapine is increasingly prescribed once daily (QD). Higher (once daily) doses may theoretically lead to saturation of protein binding of (nor)clozapine, resulting in increased unbound fractions.

Plasma esketamine and noresketamine levels and antidepressant response with oral esketamine treatment.

Objective: Oral esketamine has relatively low and variable bioavailability, which may complicate broader use as an antidepressant. This study aimed to investigate associations between different pharmacokinetic outcomes and change in depressive symptoms following oral esketamine administration in patients with treatment-resistant depression. Understanding such associations may inform dosing and administration strategies in clinical practice.

Early economic evaluation of chelation therapy in kidney transplant recipients with high-normal lead.

Background: Kidney transplant recipients (KTR) with high-normal lead have a higher risk of graft failure (GF). Clinically, chelation therapy using meso-2,3-dimercaptosuccinic acid (DMSA) removes lead. Despite the proposal that chelation therapy can prevent GF through lead removal, evidence is lacking.

Increased ferritin levels are associated with incident diabetes after kidney transplantation: A prospective cohort study.

Aim: Iron is known to play a role in glucose homeostasis, and diabetes is highly prevalent in patients with iron overload. Here, we investigated whether ferritin and hepcidin (as parameters of iron status) are associated with the development of post-transplant diabetes in kidney transplant recipients, a population in which around 10 % is known to have high iron status.

Methods: Prospective data from the TransplantLines Insulin Resistance and Inflammation Biobank and Cohort Study from the University Medical Center Groningen, the Netherlands were evaluated, involving stable adult kidney transplant recipients > 1 year after transplantation.

Clinical and Biochemical Factors Associated with Infliximab Pharmacokinetics in Paediatric Patients with Inflammatory Bowel Disease.

Monitoring infliximab (IFX) concentrations is crucial for optimizing IFX therapy in children with inflammatory bowel diseases (IBDs) who show low response rates due to inadequate drug exposure. Substantial variation occurs in IFX trough concentrations in paediatric patients. : This study aimed to investigate IFX pharmacokinetics (PK) in children with IBD during both the induction phase and maintenance phases and to identify covariates associated with IFX PK.

Improved real-world UHPLC-MS/MS iohexol analysis; thawed samples, improved calibration curve, and additional matrices.

Background: Plasma clearance of iohexol is used to measure glomerular filtration rate, for which a UHPLC-MS/MS analytical method was previously developed. In real-world conditions, samples may be thawed on arrival and sampled in unvalidated matrices, prompting the need for an improved validation. We aim to improve the method for iohexol determination in plasma with enhanced stability testing, optimized calibration curves, and partial validation in additional matrices.

Investigating the Relationship Between Midazolam Serum Concentrations and Paediatric Delirium in Critically Ill Children.

Objectives: Intravenous midazolam is widely used for sedation in critically ill children. Sometimes, these children develop a paediatric delirium (PD). Our aim was to determine the relationship between midazolam serum concentration and the development of new PD in critically ill children.

Lamotrigine Use in Lactating Women: Passage into Breast Milk and Infant Exposure: Grand Round/A Case Study.

Background: Lamotrigine, an antiseizure medication used for epilepsy and bipolar disorders, is often prescribed to women of childbearing age due to relatively low teratogenic risk. It is known that lamotrigine use in lactation leads to detectable concentrations in breast milk, although concentrations vary significantly among individuals.

Case Presentation: A 35-year-old pregnant woman with epilepsy presented to our outpatient clinic.

Dutch Pharmacogenetics Working Group (DPWG) guideline for the gene-drug interaction between SLCO1B1 and statins and CYP2C9 and sulfonylureas.

Aligned with the mission of the Dutch Pharmacogenetics Working Group (DPWG) to promote the implementation of pharmacogenetics (PGx), this guideline is specifically designed to optimize pharmacotherapy of cholesterol lowering medication (statins) and glucose lowering medication (sulfonylureas). The SLCO1B1 c.521 T > C variant reduces the activity of the SLCO1B1 transporter involved in statin transport out of the blood into the liver.

Midazolam Boosting With Cobicistat in a Patient With Drug-Resistant Epilepsy and Focal Status Epilepticus.

Background: This report presents the case of a patient with drug-resistant epilepsy. Despite treatment with 4 antiepileptic drugs, the patient experienced an increasing frequency of focal seizures, necessitating hospitalization, and continuous intravenous midazolam infusion.

Methods: Cobicistat was introduced as a pharmacokinetic booster to decrease the metabolic clearance of midazolam, leading to increased exposure and an extended half-life.

Valacyclovir Induced Neurotoxicity, with Therapeutic Drug Monitoring, in a Hospital-Based Setting in the Netherlands.

Background: Valacyclovir-induced neurotoxicity is a rare side effect. The aim of this study was to perform a retrospective analysis of patients with valacyclovir-induced neurotoxicity and establish valacyclovir plasma concentrations in a tertiary hospital between January 2018 and November 2022.

Case Descriptions: In total 208 patients were identified with measured acyclovir concentrations, and the electronic health records of these patients were analysed.

Efficacy and safety of low-dose digoxin in patients with heart failure. Rationale and design of the DECISION trial.

Aims: Digoxin is the oldest drug in cardiovascular (CV) medicine, and one trial conducted >25 years ago showed a reduction in heart failure (HF) hospitalizations but no effect on mortality. However, later studies suggested that the dose of digoxin used in that trial (and other studies) may have been too high. The DECISION (Digoxin Evaluation in Chronic heart failure: Investigational Study In Outpatients in the Netherlands) trial will examine the efficacy and safety of low-dose digoxin in HF patients with reduced or mildly reduced left ventricular ejection fraction (LVEF) with a background of contemporary HF treatment.

Clozapine levels and outcomes in Serbian patients with treatment-resistant psychotic disorders previously treated without measuring clozapine levels (CLOSER).

Clozapine remains the only pharmacological treatment option for treatment-resistant schizophrenia. Therapeutic drug monitoring (TDM) of clozapine is recommended, although evidence for the therapeutic range of 350-600 ng/ml is limited. In various countries including Serbia, TDM of clozapine is not routinely performed.

Evaluating the Clinical Impact and Feasibility of Therapeutic Drug Monitoring of Pazopanib in a Real-World Soft-Tissue Sarcoma Cohort.

Introduction And Objective: Pazopanib is registered for metastatic renal cell carcinoma and soft-tissue sarcoma (STS). Its variable pharmacokinetic (PK) characteristics and narrow therapeutic range provide a strong rationale for therapeutic drug monitoring (TDM). Prior studies have defined target levels of drug exposure (≥ 20.

Comprehensive GC-MS Measurement of Amino Acids, Metabolites, and Malondialdehyde in Metformin-Associated Lactic Acidosis at Admission and during Renal Replacement Treatment.

Metformin is the most widely used drug in type 2 diabetes. Regular metformin use has been associated with changes in concentrations of amino acids. In the present study, we used valid stable-isotope labeled GC-MS methods to measure amino acids and metabolites, including creatinine as well as malondialdehyde (MDA), as an oxidative stress biomarker in plasma, urine, and dialysate samples in a patient at admission to the intensive care unit and during renal replacement treatment because of metformin-associated lactic acidosis (MALA, 21 mM lactate, 175 µM metformin).

Reasons for non-feasibility of therapeutic drug monitoring of oral targeted therapies in oncology - an analysis of the closed cohorts of a multicentre prospective study.

Background: Therapeutic drug monitoring (TDM) - performing dose adjustments based on measured drug levels and established pharmacokinetic (PK) targets - could optimise treatment with drugs that show large interpatient variability in exposure. We evaluated the feasibility of TDM for multiple oral targeted therapies. Here we report on drugs for which routine TDM is not feasible.

Dutch Pharmacogenetics Working Group (DPWG) guideline for the gene-drug interaction between CYP2D6, CYP2C19 and non-SSRI/non-TCA antidepressants.

The Dutch Pharmacogenetics Working Group (DPWG) aims to facilitate pharmacogenetics implementation in clinical practice by developing evidence-based guidelines to optimize pharmacotherapy based on pharmacogenetic test results. The current guideline describes the gene-drug interaction between CYP2D6 and venlafaxine, mirtazapine and duloxetine. In addition, the interaction between CYP2C19 and mirtazapine and moclobemide is presented.

Impact of obesity and roux-en-Y gastric bypass on the pharmacokinetics of (R)- and (S)-omeprazole and intragastric pH.

This study employed physiologically-based pharmacokinetic-pharmacodynamics (PBPK/PD) modeling to predict the effect of obesity and gastric bypass surgery on the pharmacokinetics and intragastric pH following omeprazole treatment. The simulated plasma concentrations closely matched the observed data from non-obese, morbidly obese, and post-gastric bypass populations. Obesity significantly reduces CYP3A4 and CYP2C19 activities, as reflected by the metabolic ratio [omeprazole sulphone]/[omeprazole] and [5-hydroxy-omeprazole]/[omeprazole].

Systematic Evaluation of Osimertinib Population Pharmacokinetic Models in a Cohort of Dutch Adults with Non-Small Cell Lung Cancer.

Background And Objective: Several population pharmacokinetic (popPK) studies have been reported that can guide the prediction of osimertinib plasma concentrations in individual patients. It is currently unclear which popPK model offers the best predictive performance and which popPK models are most suitable for nonadherence management and model-informed precision dosing. Therefore, the objective of this study was to externally validate all osimertinib popPK models available in the current literature.

Infliximab in paediatric inflammatory bowel disease: External evaluation of population pharmacokinetic models.

Aims: Use of infliximab (IFX) has improved outcomes in children with inflammatory bowel disease (IBD). However, a proportion of patients does not respond to IFX or loses response over time. Population pharmacokinetic (PopPK) modelling is a promising approach for IFX dose optimization, but with the increasing number of PopPK models in literature, model evaluation is essential.