Antiepileptic drugs--best practice guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies

Levetiracetam pharmacokinetics in venovenous extracorporeal membrane oxygenation: A case report

This case report describes the pharmacokinetics of levetiracetam in a critically ill patient supported on venovenous membrane oxygenation. While levetiracetam has emerged as a first line option to treat seizures in critically ill patients, there is limited information available regarding the impact of extracorporeal membrane oxygenation on the pharmacokinetics of this medication. This report contributes to the limited body of literature describing the pharmacokinetics of medications in extracorporeal membrane oxygenation.

Use of oral anti-seizure medication via nasogastric tube to treat IV-diazepam resistant status epilepticus in a setting with limited resources: An observational study

INTRODUCTION

Despite the availability of new antiseizure medications (ASM), status epilepticus (SE) is still associated with a high mortality rate. One third of cases present with benzodiazepine resistance. The availability of intravenous ASMs in Indonesia is limited, meaning that the use of oral ASMs to treat SE is unavoidable. This study aimed to determine whether oral formulations of levetiracetam, topiramate, and valproic acid could successfully terminate diazepam-resistant SE.

METHODS

This prospective cohort study was conducted at Dr. Cipto Mangunkusumo National Hospital between June 2021 and March 2023. Patients with SE aged over 18 years, who achieved clinically apparent seizure cessation with second-line oral ASMs following diazepam, were enrolled. Plasma levels of ASMs were assessed 24 h after the last seizure. Demography, clinical characteristics, and the percentage of successful seizure termination was recorded, as well as duration of seizure termination.

RESULTS

Of the 53 participants, 33, 15, and 5 subjects were administered levetiracetam, topiramate, and valproic acid respectively. Of these, 26 (79 %), 15 (100 %), and 4 (80 %) achieved seizure termination. The median dose required to terminate clinically apparent seizures for oral formulations of levetiracetam, topiramate, and valproic acid were 23 mg/kg, 6 mg/kg, and 20 mg/kg. Seizure termination duration was significantly longer in the topiramate group. Median plasma levels (µg/ml) for levetiracetam, topiramate, and valproic acid among subjects who achieved seizure termination with one second-line ASM were 18.3, 9.5, and 43.2. The 30-day mortality rate among subjects administered levetiracetam, topiramate, and valproic acid, was 15 %, 53 %, and 40 %, respectively.

CONCLUSION

Oral ASMs can be a viable option for the treatment of diazepam-resistant SE in settings with limited resources, where intravenous formulations are not attainable.

Non-invasive therapeutic drug monitoring: LC-MS validation for lamotrigine quantification in dried blood spot and oral fluid/saliva

Epilepsy, affecting over 50 million people globally, presents a significant neurological challenge. Effective prevention of epileptic seizures relies on proper administration and monitoring of Anti-Seizure Medication (ASMs). Therapeutic Drug Monitoring (TDM) ensures optimal dosage adjustment, minimizing adverse effects and potential drug interactions. While traditional venous blood collection for TDM may be stressful, emerging alternative sampling methods, particularly Dried Blood Spot (DBS) or oral fluid offer less invasive way of sampling. This study aimed to develop and validate an analytical method for the determination of lamotrigine in such alternative samples. The sample, either DBS or oral fluid, was subjected to extraction, evaporation, and reconstitution in 15 % acetonitrile containing 0.1 % formic acid. A Kinetex C18 Polar column was used for liquid chromatographic separation and MS in ESI+ mode was used for detection and quantitation of lamotrigine using an isotopically labelled internal standard according to EMA guidelines. The calibration range of the developed method enables the determination of lamotrigine in the concentration range of 1-30 μg/mL in DBS and 0.5-20 μg/mL in oral fluid. Oral fluid and DBS samples from patients treated with lamotrigine analysed by the developed method were compared to plasma concentrations measured by the hospital's accredited laboratory. Preliminary results indicate a promising potential for these alternative matrices in clinical TDM applications. By offering a less invasive sampling approach, this method improves the accessibility and safety of pharmacotherapy for epilepsy patients. The results of this study lay the foundation for further clinical applications by implementing alternative matrix TDM, which may significantly advance personalized care in epilepsy management.

Population pharmacokinetics of cannabidiol and the impact of food and formulation on systemic exposure in children with drug-resistant developmental and epileptic encephalopathies

OBJECTIVE

Identifying factors influencing cannabidiol (CBD) exposure can optimize treatment efficacy and safety. We aimed to describe the population pharmacokinetics of CBD in children with drug-resistant developmental and epileptic encephalopathies (DEEs) and assess the influence of environmental, pharmacological, and clinical characteristics on CBD systemic exposure.

METHODS

Data from two pharmacokinetic studies of patients aged 2-18 years with DEEs were included (N = 48 patients). Serial blood samples were collected during maintenance treatment, before and after the morning dose, and up to 6 h after a dose of a purified CBD oil formulation, with or without a normocaloric breakfast. CBD plasma concentrations were also available following administration of a CBD-enriched formulation. Samples were quantified using a validated liquid chromatography/tandem mass spectrometry assay. A CBD population pharmacokinetic model was developed using nonlinear mixed-effects modeling. The effects of formulation, concomitant food intake, and demographic, clinical, and pharmacological factors on CBD pharmacokinetics were evaluated. Simulated maximum plasma concentration (Cmax) and area under the concentration-time curve between 0 and 12 h (AUC0-12) were calculated.

RESULTS

A one-compartment model with transit compartments and first-order elimination best described CBD pharmacokinetics. Mean values for CBD apparent clearance (CL/F) and volume of distribution (V/F) were 143.5 L/h and 1892.4 L, respectively. Weight was allometrically scaled for V/F and CL/F, sex was associated with V/F, and both formulation and food condition were associated with F (relative bioavailability). CBD Cmax increased by 41% and AUC0-12 by 45% when CBD was administered with food compared to fasting. Dose-normalized AUC0-12 was approximately 50% lower with CBD-enriched oil compared to purified CBD.

SIGNIFICANCE

In the present study, we described the effects of food and formulation on CBD exposure in children with DEEs. Increased CBD exposure with food intake and significant changes in drug exposure when switching between CBD formulations should be considered in patient management.

A new population pharmacokinetic model for dosing optimization of zonisamide in patients with refractory epilepsy

Zonisamide exhibits significant pharmacokinetic variability, demanding for the development of population pharmacokinetic (PopPK) models to identify key factors influencing drug disposition. This study aimed to develop and validate a PopPK model to optimize zonisamide posology in patients with refractory epilepsy. A total of 114 plasma concentrations of zonisamide, obtained from 64 patients, were used for PopPK model development, employing the nonlinear mixed-effects modelling approach. The final model was evaluated by visually inspecting the goodness-of-fit plots and the visual predictive check plot and by the bootstrap resampling method. A one-compartment model with first-order elimination was the one that best described the pharmacokinetic profile of zonisamide. Between-patient variability (BPV) was included on clearance (CL/F), volume of distribution (Vd/F) and absorption rate constant (ka). The residual error (RE) was modeled as proportional. The final model estimates for CL/F, Vd/F and ka were 0.761 L/h, 48.10 L and 0.671 h⁻¹, respectively. The BPV associated with CL/F, Vd/F, and ka was 43.93%, 52.06%, and 91.27%, respectively, while the proportional RE was 7.18%. The concomitant administration of enzyme-inducing antiseizure drugs (EIASDs), included in the model as inducer drug load (INDDL), significantly accounted for BPV associated with CL/F and led to increased CL/F in patients receiving EIASDs compared to the others. Consequently, patients receiving EIASDs require higher daily doses of zonisamide to achieve therapeutic plasma concentrations compared to those not treated with EIASDs. Model validation, using bootstrap and visual predictive checks, confirmed its stability and robustness, making it a valuable tool for individualized zonisamide dosing in adults with refractory epilepsy.

Ethosuximide-associated Aplastic Anemia Likely Due to Drug-induced Lupus Erythematosus: A Case Report With Immunologic Insights

Ethosuximide-associated aplastic anemia (AA) is a rare idiosyncratic disorder with unclear etiology. We report a 17-year-old female with absence seizures on ethosuximide, who was incidentally found to have pancytopenia and a markedly hypocellular marrow (<5% cellularity) with lupus erythematosus (LE) cells. The presence of antinuclear and anti-histone antibodies supported a diagnosis of AA secondary to drug-induced lupus erythematosus. Ethosuximide was discontinued, and prednisone started with marked blood count recovery. Our case is the first to elucidate the particular lupus erythematosus association, as evidenced by the combination of immunologic serology, marrow aplasia, and the presence of marrow LE cells.

The impact of menstrual cycle on the pharmacokinetics of antiseizure medications and lithium: a systematic review and meta-analysis

INTRODUCTION

Our aim was to quantify the impact of menstrual cycle phases on the pharmacokinetics of antiseizure medications (ASM) and lithium.

METHODS

A systematic literature search was conducted in PubMed/EMBASE in March 2024 for studies comparing levels of ASM and/or lithium in the early follicular and luteal phase. Concentration ratios between the follicular and the luteal phase were calculated. We performed a random-effects meta-analysis calculating between-timepoint differences in plasma concentration mean differences (MDs) and 95% confidence intervals (95% CIs). Subgroup analyses included cohorts stratified by the occurrence of catamenial exacerbation. Study quality was assessed using the ClinPK guidelines.

RESULTS

Fifteen studies investigating six ASM and lithium in 224 subjects were included. The highest concentration ratio was reported for carbamazepine (1.27, range 0.89-2.13) with an MD of 0.57 μg/mL, 95% CI: 0.41 to 0.72. Phenytoin concentration fluctuations were larger in subjects with (MD -3.51 μg/mL, 95% CI = -4.97 to -2.06) vs. without catamenial exacerbations (MD -1.18 μg/mL, 95% CI = -2.51 to 0.14, p = 0.02). Study quality was acceptable with an average rating score of 13.1.

CONCLUSIONS

Data do not suggest major changes in ASM pharmacokinetics across the menstrual cycle. Participants with vs. without catamenial exacerbation had larger phenytoin concentration decreases in the early follicular compared to the luteal phase.

PROTOCOL REGISTRATION

www.crd.york.ac.uk/prospero identifier is CRD42024527321.

Sex-specific UGT expression and function: prevalence, potential mechanisms and significance

INTRODUCTION

Sex and gender influence pharmacotherapy outcomes, including adverse drug effects which are nearly twice as common in women. Sex differences in drug responses involve factors as diverse as body composition, physiology, and prescribing patterns. Many drugs show higher exposure in women, which can be partly attributed to sex-differences in processes that control drug disposition such as metabolism and transport.

AREAS COVERED

This article reviews sex differences in the expression and function of the critical phase II drug-metabolizing enzymes, UDP-glucuronosyltransferases (UGTs). We curate the literature on sex-biased UGT expression in human tissues, describe the evidence for UGT-mediated sex-differences in drug exposure, and critically evaluate whether UGTs contribute to different drug outcomes in males and females. Relevant literature was identified by searching PubMed with terms including UDP-glucuronosyltransferase/UGT, glucuronidation/glucuronide, sex, gender, male, female, men, and women.

EXPERT OPINION

Several examples of sex-biased UGT expression and drug glucuronidation were identified; however, evidence of clinical impact was more limited. Significant data gaps limit our understanding of the prevalence and importance of sex-biased glucuronidation. Novel methodologies for tissue-level metabolite sampling together with increased sex-aware analysis of clinical/preclinical data, could help address gaps and reveal new avenues for enhancing pharmacotherapy outcomes for all genders.

Valproic acid-induced teratogenicity is driven by senescence and prevented by Rapamycin in human spinal cord and animal models

Valproic acid (VPA) is an effective and widely used anti-seizure medication but is teratogenic when used during pregnancy, affecting brain and spinal cord development for reasons that remain largely unclear. Here we designed a genetic recombinase-based SOX10 reporter system in human pluripotent stem cells that enables tracking and lineage tracing of Neural Crest cells (NCCs) in a human organoid model of the developing neural tube. We found that VPA induces extensive cellular senescence and promotes mesenchymal differentiation of human NCCs. We next show that the clinically approved drug Rapamycin inhibits senescence and restores aberrant NCC differentiation trajectory after VPA exposure in human organoids and in developing zebrafish, highlighting the therapeutic promise of this approach. Finally, we identify the pioneer factor AP1 as a key element of this process. Collectively our data reveal cellular senescence as a central driver of VPA-associated neurodevelopmental teratogenicity and identifies a new pharmacological strategy for prevention. These results exemplify the power of genetically modified human stem cell-derived organoid models for drug discovery.

Two Cases of Levetiracetam-Induced Rhabdomyolysis With Low Levetiracetam Blood Concentrations

Levetiracetam is an antiepileptic drug used to treat tonic-clonic convulsions and partial seizures. In general, levetiracetam is well tolerated; however, rhabdomyolysis has been reported as a rare side effect. The underlying mechanism is unclear. This case report describes two cases of rhabdomyolysis during levetiracetam treatment for convulsive status epilepticus, both of whom developed rhabdomyolysis a few days after starting levetiracetam. When levetiracetam was replaced with lacosamide, creatinine kinase decreased to the normal range within approximately 10 days. Furthermore, blood levels of levetiracetam were measured at the onset of rhabdomyolysis, and the results suggest that its adverse effects may not be correlated with its levels in the blood. Monitoring creatinine kinase is important for early detection of levetiracetam-induced rhabdomyolysis.

Development of a 3D printed chemiluminescence smartphone detector for high performance liquid chromatography

A novel chemiluminescence detector for high-performance liquid chromatography (HPLC) was designed that incorporates a smartphone as photodetector, signal processor, and data storage unit. All detector components, including flow cell, flow cell holder, mixers, and housing, were fabricated by 3D printing and integration of the smartphone and 3D printed components provides a portable, low-cost, and user-friendly device. The detector was applied in the determination of carbamazepine using HPLC through a chemiluminescence reaction with tris(2,2'-bipyridyl)ruthenium(II) and cerium sulfate. Design and fabrication of the flow cell using two fabrication methods-3D printing and laser cutting-along with the integration of a mixer and the optimization of smartphone parameters were investigated. To expand the applicability of the detector for other analytes and different chemiluminescence reactions, detection of three piperazine derivatives by reaction with tris(2,2'-bipyridyl)ruthenium(II) and four phenethylamine compounds via reaction with acidic potassium permanganate reagent was studied. The linear dynamic range, limit of detection, and limit of quantification of the detector for the determination of carbamazepine were measured as 3.0-30.0 mg/L, 1.0 mg/L, and 3.0 mg/L, respectively, using the Samsung S20 smartphone device. Intraday and interday precision was evaluated for carbamazepine, with relative standard deviation (RSD) values for intraday precision ranging from 1.7 % to 6.2 % (n = 3) and interday precision RSD values ranging from 3.2 % to 4.8 % (n = 9).

Levetiracetam dosing in continuous renal replacement therapy: A systematic review and development of a novel pharmacokinetic model to optimise dosing in critically ill patients. Do recommended doses achieve therapeutic drug concentrations?

Aim

Levetiracetam is a widely used anti-epileptic in the critical care setting that is almost exclusively (>90%) renally excreted. The altered pharmacokinetics of levetiracetam have been widely studied in intermittent haemodialysis but the evidence and guidance on dosage in continuous renal replacement therapy is varied and poorly defined. Understanding this is critical as a significant number of critically unwell patients develop renal failure requiring continuous renal replacement therapy. The aim of this systematic review is to investigate the pharmacokinetics of levetiracetam in such patients and to understand the implications on dosing strategies.

Methods

A systematic review of the available literature from 2000 to November 2022 was conducted. Seven articles were identified for inclusion from 54 records. A novel hybrid model was developed to evaluate the quality of pharmacokinetic and haemofiltration data. This data was used to develop a one-compartment model that simulated dosing strategies in 10,000 patients based on an assumed steady state of 72 hr and target trough concentrations of 12-46 mcg/mL.

Results

From the seven articles included, pharmacokinetic data was retrieved for 24 individual patients. Total clearance was 3.49-4.63 L/hr (mean 3.55, S.D. 0.52). Elimination half-life was 5.66-12.88 hr (mean 9.41, S.D. 2.86). Volume of distribution was 0.45-0.73 L/kg. The proportion of total clearance attributable to continuous renal replacement therapy was 52%-73% (mean 54.7%, S.D. 13.5). Our simulations demonstrate that more than half of patients who received twice daily doses of 750 mg or greater without a loading dose achieved therapeutic drug concentrations. The time to achievement of therapeutic drug concentrations was greatly reduced by the addition of a 60 mg/kg loading dose (up to a maximum of 4.5 g). The use of a reduced loading dose or twice daily doses of 500 mg or less without loading were more likely to result in prolonged sub-therapeutic drug concentrations.

Conclusion

Levetiracetam clearance in haemofiltration is similar to healthy adults with normal renal function (GFR > 90 mL/min). The use of reduced doses due to renal failure in critically ill patients may result in sub-therapeutic drug concentrations in a high number of patients. A twice daily dosing of 750-1000 mg with an initial loading dose of 60 mg/kg should be considered in such patients alongside therapeutic drug monitoring.

Pharmacokinetic variability and use of therapeutic drug monitoring of cannabidiol in patients with refractory epilepsy

OBJECTIVE

Cannabidiol (CBD) (Epidyolex) is a new antiseizure medication (ASM) for rare and severe epileptic syndromes. We aimed to investigate the pharmacokinetic variability of CBD to elucidate relationships between doses, serum concentrations, metabolites, and biochemical markers of toxicity by using therapeutic drug monitoring (TDM) data.

METHODS

Data on serum concentrations of all ASMs, CBD, and the active metabolite 7-hydroxy-cannabidiol (7-OH-CBD) were collected (January 2022 to June 2023) at the Section for Clinical Pharmacology, National Centre for Epilepsy, Oslo University Hospital.

RESULTS

Data from 52 patients were included: 122 serum concentration measurements (1-7 per patient); 48% female, mean age 23 (range 3-55) years. At maintenance (n = 34), the mean daily dose was 535 (SD 224) mg, that is, 10.03 (standard deviation [SD] .49) mg/kg/day, serum concentration .26 (SD .14) for CBD and .13 (SD .10) μmol/L for 7-OH-CBD. Reference ranges of .15-.50 μmol/L for CBD and .04-.25 μmol/L for 7-OH-CBD are proposed, which included 80% of measurements. There was a linear correlation between CBD dose to concentration and CBD to CBD-7-OH concentrations (r2 = .39 and .38) (p < .05). The hepatic marker alanine aminotransferase (ALT) increased on average 37%, demonstrating a moderate effect on liver function. Intra-individual coefficients of variation (CVs) were 32% (SD 17) for CBD and 48% (SD 24) for 7-OH-CBD (n = 15, ≥3 measurements). Twenty different ASMs were used: clobazam (n = 24), valproate (n = 17), and stiripentol (n = 8) were most common. The mean concentration ratio of desmethyl-clobazam/clobazam increased by 140% (7.29-17.5; p < .05) but was variable, pointing to enzyme inhibition by CBD.

SIGNIFICANCE

This observational study with TDM data revealed extensive pharmacokinetic variability of CBD in patients with refractory epilepsy. The results demonstrate the need for close follow-up and use of TDM, including biochemical markers of toxicity, for individualized treatment with CBD.

The Impact of Augmented Renal Clearance on the Pharmacokinetics of Levetiracetam in Critically Ill Patients: A Literature Review

Levetiracetam is an antiseizure medication (ASM) that has several advantages over other ASMs, such as dose-proportional pharmacokinetics, high bioavailability, and minimal drug interactions. The drug is primarily eliminated through the kidneys. Therefore, dose adjustments are necessary in patients with renal impairment or patients experiencing augmented renal clearance (ARC) to maintain optimal efficacy and safety. The objective of this review was to explore the existing literature on the influence of ARC on the pharmacokinetics of levetiracetam in critically ill patients. Database searched included MEDLINE, Embase, Scopus, Cochrane Library, and CINAHL. Thirteen articles were included. The prevalence of ARC ranged from 30% to 90%. All studies demonstrated the inadequacy of the levetiracetam starting dose of 500 mg twice daily (BID) in critically ill patients. Studies consistently reported altered pharmacokinetics of levetiracetam in patients with ARC, showing an elevated clearance that can reach up to 6.5L/h (∼3.8 L/h in healthy individuals). Additionally, patients with ARC had a lower area under the concentration-time curve, shorter half-life, and lower trough concentrations than those without ARC. Dosing simulations indicated that the use of at least 1500 mg BID is recommended for ARC patients to achieve similar exposures to those with no ARC on the 1000 mg BID starting dose. In conclusion, ARC significantly enhances the renal elimination of levetiracetam, elevating the risk of sub-therapeutic drug levels and treatment failure. An initial dosage regimen of 1500 mg BID would be recommended for patients exhibiting ARC. Therefore, careful monitoring of creatinine clearance and dosing optimization for patients experiencing ARC is essential.

Hyaluronic acid-based hydrogels as codelivery systems: The effect of intermolecular interactions investigated by HR-MAS and solid-state NMR Spectroscopy

Hydrogels based on hyaluronic acid and agarose-carbomer, due to their peculiar 3D architecture and biocompatibility, are promising candidates for pharmaceutical strategies based on the codelivery of drugs targeting different diseases. The successful development of these applications requires a precise understanding of drug-drug interactions and their effects on transport and release mechanisms. In this study, such an investigation is carried out on hydrogels loaded with ethosuximide and sodium salicylate at different concentrations. Intermolecular interactions and transport properties are characterized by means of High Resolution Magic Angle Spinning and solid-state Magic Angle Spinning NMR Spectroscopy. At variance with our previous findings on single-drug formulations, the two drugs exhibit closely similar diffusion patterns when co-loaded in the HA-based hydrogels, plausibly due to drug-drug intermolecular interactions. At the highest drug concentrations, where superdiffusion comes into play, we find a fraction of molecules with time-varying diffusion coefficients. A trapping-release mechanism is proposed to explain this observation, which also accounts for the role of drug-hydrogel interactions in drug diffusion motion. The effects of drug-drug interactions on release profiles are finally assessed by means of in vitro release experiments.

Clinical value of saliva therapeutic drug monitoring of newer antiseizure medications

INTRODUCTION

Saliva is a promising option for therapeutic drug monitoring, with studies since the 1970s indicating a good correlation between plasma and saliva levels for early anti-seizure medications, although limited data exist for newer generation drugs.

OBJECTIVES

To evaluate the reliability and predictive power of saliva as a minimally invasive surrogate marker of plasma concentration for the routine therapeutic drug monitoring (TDM) of newer anti-seizure medications (ASM).

METHODS

We collected blood samples at steady state in patients at least 6 h post-dose, paired with unstimulated saliva samples. We evaluated the correlation between plasma and saliva drug levels and the positive and negative predictive value for plasma values extrapolation from saliva levels. A very low saliva level was defined as below half the plasma lower reference limit.

RESULTS

294 adult patients (53 % male) with a mean age of 40 (SD: 16) were enrolled and 589 paired saliva-plasma samples were quantified. The highest significant correlations between saliva and plasma were observed for zonisamide (R2: 0.92) perampanel (0.91), brivaracetam (0.87), followed by topiramate, lamotrigine, lacosamide (0.76-0.68), and rufinamide, levetiracetam, pregabalin (0.63-0.55). No significant correlation was found for the active mono-hydroxy derivative of oxcarbazepine. Despite a good correlation coefficient, the correlations between saliva and plasma levels were generally loose, resulting in a broad predicted range of plasma levels for a given saliva level. Nonetheless, very low saliva levels exhibited strong specificity in predicting low plasma levels, with 87 % to 100 % accuracy, and when saliva levels fell below the limit of quantification, all corresponding plasma levels were below reference ranges.

CONCLUSIONS

This large newer ASM paired plasma-saliva collection allows to precise the potential use of saliva in the management of epilepsy, especially for commonly used ASM such as lamotrigine and levetiracetam. Although they correlate well, extrapolating plasma levels from saliva samples is still an imprecise approximation, making it inadequate for fine dosage adjustments. Yet, a very low saliva level has an appreciable discriminative ability for low plasma level. Unstimulated saliva represents a convenient non-invasive alternative to plasma, to readily identify compliance issues or major drug-drug interactions.

Technological advances in clinical individualized medication for cancer therapy: from genes to whole organism

Efforts have been made to leverage technology to accurately identify tumor characteristics and predict how each cancer patient may respond to medications. This involves collecting data from various sources such as genomic data, histological information, functional drug profiling, and drug metabolism using techniques like polymerase chain reaction, sanger sequencing, next-generation sequencing, fluorescence in situ hybridization, immunohistochemistry staining, patient-derived tumor xenograft models, patient-derived organoid models, and therapeutic drug monitoring. The utilization of diverse detection technologies in clinical practice has made "individualized treatment" possible, but the desired level of accuracy has not been fully attained yet. Here, we briefly summarize the conventional and state-of-the-art technologies contributing to individualized medication in clinical settings, aiming to explore therapy options enhancing clinical outcomes.

ABCB1 Polymorphism Is Associated with Higher Carbamazepine Clearance in Children

The aim of our study was to investigate the role of ABCB1 polymorphism in the pharmacokinetics of carbamazepine (CBZ) in children. The study enrolled 47 Serbian pediatric epileptic patients on CBZ treatment. Genotyping for ABCB1 1236C Collapse

Key Words

• ABCB1
• carbamazepine
• children
• genetic polymorphism
• population pharmacokinetics

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Grants

• 175007 and 175056 the Ministry of Science and Technology of the Republic of Serbia
• 07/11 Faculty of Medical Sciences, University of Kragujevac, Serbia

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Affiliation(s)

Natasa Djordjevic Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (J.R.M.); (S.J.); (D.M.)
Jelena Cukic Public Health Institute, Nikole Pasica 1, 34 000 Kragujevac, Serbia; (J.C.); (D.B.)
Dragana Dragas Milovanovic College of Professional Health Studies, Cara Dusana 254, 11 080 Belgrade, Serbia;
Marija Radovanovic Department of Pediatrics, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (M.R.); (S.O.)
Ivan Radosavljevic Department of Surgery, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia;
Jelena Vuckovic Filipovic Department of Internal Medicine, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia;
Slobodan Obradovic Department of Pediatrics, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (M.R.); (S.O.)
Dejan Baskic Public Health Institute, Nikole Pasica 1, 34 000 Kragujevac, Serbia; (J.C.); (D.B.) Department of Microbiology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia
Jasmina R. Milovanovic Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (J.R.M.); (S.J.); (D.M.)
Slobodan Jankovic Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (J.R.M.); (S.J.); (D.M.)
Dragan Milovanovic Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia; (J.R.M.); (S.J.); (D.M.)

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A Clinical Nomogram for Predicting Substandard Serum Valproic Acid Concentrations in Chinese Patients With Epilepsy

Background

It is well-known that substandard serum valproic acid (VPA) concentrations may lead to treatment failure of epilepsy. However, there is still a lack of a quick method to predict whether a patient's serum VPA concentration will reach the standard.

Objective

The aims of this study were to investigate the factors leading to substandard serum VPA concentrations in Chinese patients with epilepsy and develop a related nomogram for risk prediction.

Methods

From January 2019 to March 2022, a total of 1143 serum VPA concentrations were collected from 630 hospitalized Chinese patients with epilepsy who were monitored by the Department of Pharmacy of Lu'an People's Hospital, and complete clinical data were collected from the corresponding patients for retrospective analysis. All monitored serum VPA concentrations were further divided into a training cohort and a validation cohort. For the training cohort, serum VPA concentrations below 50 µg/mL and between 50 and 100 µg/mL were classified into the subtherapeutic group and therapeutic group, respectively. The variables were selected from the clinical data, and differences between the variables of the subtherapeutic and therapeutic groups were analyzed. The influencing factors leading to substandard serum VPA concentrations were screened via logistic regression analysis, and the screened influencing factors were used to establish the nomogram prediction model.

Results

Multivariate logistic regression analysis revealed that the daily dose per unit of body weight (mg/kg/d), route of administration, presence of hepatic lesions, hypoalbuminemia, and combination with carbapenems or barbiturates were independent factors influencing the occurrence of substandard serum VPA concentrations. On the basis of the results of the multivariate logistic regression analysis, a nomogram risk prediction model for substandard serum VPA concentration was established. The values of the C-index and internal verification results indicated that the nomogram model had good accuracy and discrimination. The decision curve revealed that the nomogram that predicted the risk of substandard serum VPA concentration had a greater net benefit value (ranging from 12% to 94%), indicating that the model had a wide prediction interval.

Conclusions

Our study established a nomogram risk prediction model for substandard serum VPA concentrations in Chinese patients with epilepsy, which can help doctors or patients control the serum VPA concentration within the target concentration range as soon as possible.

Subchronic Treatment with CBZ Transiently Attenuates Its Anticonvulsant Activity in the Maximal Electroshock-Induced Seizure Test in Mice

The objective of this study is to evaluate the anticonvulsant efficacy of carbamazepine (CBZ) following acute and chronic administration across four treatment protocols in a murine model of maximal electroshock-induced seizures. A single dose of the drug was utilized as a control. The neurotoxic effects were evaluated in the chimney test and the passive avoidance task. Furthermore, plasma and brain concentrations of CBZ were quantified across all treatment protocols. The subchronic administration of CBZ (7 × 2 protocol) resulted in an attenuation of its antielectroshock effect. In the three remaining treatment regimens (7 × 1, 14 × 1, and 14 × 2) the median effective doses of CBZ were comparable to the control. Neither acute nor chronic treatment with CBZ resulted in a discernible impact on motor coordination or long-term memory. The plasma and brain concentrations of CBZ were significantly lower in most chronic protocols when compared to a single-dose application. This may explain the transient attenuation of CBZ effectiveness in the 7 × 2 protocol, but not the return to the previous level. The anticonvulsant and neurotoxic profiles of CBZ did not differ after single and chronic administration. Therefore, experimental chronic studies with CBZ are not prerequisites for concluding and possibly translating results to clinical conditions.

A comparison of the antiepileptogenic efficacy of two rationally chosen multitargeted drug combinations in a rat model of posttraumatic epilepsy

Post-traumatic epilepsy (PTE) is a recurrent and often drug-refractory seizure disorder caused by traumatic brain injury (TBI). No single drug treatment prevents PTE, but preventive drug combinations that may prophylax against PTE have not been studied. Based on a systematic evaluation of rationally chosen drug combinations in the intrahippocampal kainate (IHK) mouse model of acquired epilepsy, we identified two multi-targeted drug cocktails that exert strong antiepileptogenic effects. The first, a combination of levetiracetam (LEV) and topiramate, only partially prevented spontaneous recurrent seizures in the model. We therefore added atorvastatin (ATV) to the therapeutic cocktail (TC) to increase efficacy, forming "TC-001". The second cocktail - a combination of LEV, ATV, and ceftriaxone, termed "TC-002" - completely prevented epilepsy in the mouse IHK model. In the present proof-of-concept study, we tested whether the two drug cocktails prevent epilepsy in a rat PTE model in which recurrent electrographic seizures develop after severe rostral parasagittal fluid percussion injury (FPI). Following FPI, rats were either treated over 3-4 weeks with vehicle or drug cocktails, starting either 1 or 4-6 h after the injury. Using mouse doses of TC-001 and TC-002, no significant antiepileptogenic effect was obtained in the rat PTE model. However, when using allometric scaling of drug doses to consider the differences in body surface area between mice and rats, PTE was prevented by TC-002. Furthermore, the latter drug cocktail partially prevented the loss of perilesional cortical parvalbumin-positive GABAergic interneurons. Plasma and brain drug analysis showed that these effects of TC-002 occurred at clinically relevant levels of the individual TC-002 drug components. In silico analysis of drug-drug brain protein interactions by the STITCH database indicated that TC-002 impacts a larger functional network of epilepsy-relevant brain proteins than each drug alone, providing a potential network pharmacology explanation for the observed antiepileptogenic and neuroprotective effects observed with this combination.

Taprenepag restores maternal-fetal interface homeostasis for the treatment of neurodevelopmental disorders

BACKGROUND AND PURPOSE

Neurodevelopmental disorders (NDDs) are characterized by abnormalities in brain development and neurobehaviors, including autism. The maternal-fetal interface (MFI) is a highly specialized tissue through which maternal factors affect fetal brain development. However, limited research exists on restoring and maintaining MFI homeostasis and its potential impact on NDDs. This study explores the role of placental indoleamine 2,3-dioxygenase (IDO-1) in MFI homeostasis and fetal brain development.

EXPERIMENTAL APPROACH

The maternal-fetal barrier was disrupted by sodium valproate (VPA) in pregnant mice, whose offspring show typical autism-like behaviors. Ultrastructural analysis and flow cytometric analysis were conducted to observe the morphological and immune system changes. Behavioral tests and immunofluorescence staining was used to investigate the ability and mechanism of taprenepag to alleviate the abnormal behaviors of VPA-exposed offspring and normalize the development of serotonergic neurons.

KEY RESULTS

In VPA-exposed pregnant mice, the downregulation of IDO-1 led to maternal immune overactivation and disruption of maternal-fetal barrier, resulting in excessive 5-HT synthesis in the placenta. This process disrupted the development of the serotonergic neuronal system in the offspring, resulting in impaired development of serotonergic neurons, thalamocortical axons, and NDDs in the progeny. However, a single injection of taprenepag at E13.5 ultimately upregulated placental IDO-1 through amplifying the positive feedback loop COX-2/PGE2/PTGER-2/IDO-1 and abolished these alterations.

CONCLUSION

Taprenepag improved autism-like behaviors in the offspring of VPA-exposed mice by addressing placental IDO-1 downregulation. This study highlights the potential of targeting IDO-1 to mitigate MFI disruption and NDD development.

Handling delayed or missed direct oral anticoagulant doses: model-informed individual remedial dosing

ABSTRACT

Nonadherence to direct oral anticoagulant (DOAC) pharmacotherapy may increase the risk of thromboembolism or bleeding, and delayed or missed doses are the most common types of nonadherence. Current recommendations from regulatory agencies or guidelines regarding this issue lack evidence and fail to consider individual differences. This study aimed to develop individual remedial dosing strategies when the dose was delayed or missed for DOACs, including rivaroxaban, apixaban, edoxaban, and dabigatran etexilate. Remedial dosing regimens based on population pharmacokinetic (PK)-pharmacodynamic (PD) modeling and simulation strategies were developed to expeditiously restore drug concentration or PD biomarkers within the therapeutic range. Population PK-PD characteristics of DOACs were retrieved from previously published literature. The effects of factors that influence PK and PD parameters were assessed for their impact on remedial dosing regimens. A web-based dashboard was established with R-shiny to recommend remedial dosing regimens based on patient traits, dosing schedules, and delay duration. Addressing delayed or missed doses relies on the delay time and specific DOACs involved. Additionally, age, body weight, renal function, and polypharmacy may marginally affect remedial strategies. The proposed remedial dosing strategies surpass current recommendations, with less deviation time beyond the therapeutic range. The online dashboard offers quick and convenient solutions for addressing missed or delayed DOACs, enabling individualized remedial dosing strategies based on patient characteristics to mitigate the risks of bleeding and thrombosis.

Molecular Nanoinformatics Approach Assessing the Coating Oxcarbazepine (OXC) Drug on Silver Nanoparticles

Silver nanoparticles (AgNP) have gained significant attention due to their unique pharmacological properties. These nanoparticles have been found to possess antimicrobial, anti-inflammatory, and antioxidant activities, making them promising candidates for various medical applications. The coating characteristics of oxcarbazepine (OXC), a drug used in epilepsy treatment, on the AgNP icosahedral clusters were investigated using molecular dynamics (MD) simulations and noncovalent interactions (NCI) and Independent Gradient Model (IGM) analysis. We investigated the AgNP coating using OXC drug concentrations of 500, 1000, 1500, 2000, and 2500 ppm. Our results suggested that the OXC drug has a high potential interaction with the AgNP, especially when the concentration increases. Furthermore, it was observed that this interaction occurs mainly through the nitrogen atom (N1) of the OXC molecule, independent of concentration. Finally, the coating is more pronounced for high OXC concentrations. The weak interaction analysis indicated that the van der Waals interactions were observed between the OXC molecules and AgNP, resulting in relevant stability in these interactions. Therefore, our study may be helpful for experimental research groups to develop an oxcarbazepine drug delivery system using AgNP.

Factors associated with subtherapeutic levels of valproic acid in hospitalized patients with epilepsy: A retrospective cohort study

Valproic acid (VPA) is a commonly used anti-seizure medication, owing to its efficacy and cost-effectiveness. However, maintaining appropriate serum levels is crucial due to the narrow therapeutic window, as subtherapeutic levels can lead to treatment failure or adverse outcomes. This study aimed to identify the factors associated with subtherapeutic serum levels of valproic acid in patients undergoing treatment. This retrospective cohort study was performed at a tertiary care hospital and involved inpatients aged ≥ 18 years who were receiving valproic acid for epilepsy treatment. Data were obtained through chart reviews and a Therapeutic Drug Monitoring database. Subtherapeutic VPA levels were defined as < 50 mg/L. Logistic regression was used to identify risk factors for subtherapeutic levels. Of the 152 patients, 96 (63.2%) had subtherapeutic VPA levels (<50 mg/L). Males were more likely than females to have subtherapeutic levels (OR 2.45, 95% CI: 1.15-5.22; P = .02). Previous use of phenytoin significantly increased the risk of subtherapeutic VPA levels (OR 2.58, 95% CI: 1.16-5.71; P = .02). VPA administration by syrup and doses below 15 mg/kg/day were associated with subtherapeutic levels (OR 3.28 and 2.34, respectively). Additionally, co-medications, such as topiramate and meropenem, also increased this risk (OR 5.09 and 4.64, respectively). This study identified several factors significantly associated with subtherapeutic levels of valproic acid, including males, prior phenytoin use, co-medications, such as topiramate and meropenem, and lower VPA dosages. These findings underscore the importance of careful monitoring and individualized treatment plans to maintain therapeutic VPA levels in clinical practice. Further research is needed to explore the clinical implications and to develop strategies to minimize the risk of subtherapeutic levels in patients receiving VPA.

Anchoring temporal convolutional networks for epileptic seizure prediction

Objective. Accurate and timely prediction of epileptic seizures is crucial for empowering patients to mitigate their impact or prevent them altogether. Current studies predominantly focus on short-term seizure predictions, which causes the prediction time to be shorter than the onset of antiepileptic, thus failing to prevent seizures. However, longer epilepsy prediction faces the problem that as the preictal period lengthens, it increasingly resembles the interictal period, complicating differentiation.Approach. To address these issues, we employ the sample entropy method for feature extraction from electroencephalography (EEG) signals. Subsequently, we introduce the anchoring temporal convolutional networks (ATCN) model for longer-term, patient-specific epilepsy prediction. ATCN utilizes dilated causal convolutional networks to learn time-dependent features from previous data, capturing temporal causal correlations within and between samples. Additionally, the model also incorporates anchoring data to enhance the performance of epilepsy prediction further. Finally, we proposed a multilayer sliding window prediction algorithm for seizure alarms.Main results. Evaluation on the Freiburg intracranial EEG dataset shows our approach achieves 100% sensitivity, a false prediction rate (FPR) of 0.09 per hour, and an average prediction time (APT) of 98.92 min. Using the CHB-MIT scalp EEG dataset, we achieve 97.44% sensitivity, a FPR of 0.12 per hour, and an APT of 93.54 min.Significance. These results demonstrate that our approach is adequate for seizure prediction over a more extended prediction range on intracranial and scalp EEG datasets. The APT of our approach exceeds the typical onset time of antiepileptic. This approach is particularly beneficial for patients who need to take medication at regular intervals, as they may only need to take their medication when our method issues an alarm. This capability has the potential to prevent seizures, which will greatly improve patients' quality of life.

Fixed parameters in the population pharmacokinetic modeling of valproic acid might not be suitable: external validation in Chinese adults with epilepsy or after neurosurgery

PURPOSE

This study aims to assess the predictive performance of published valproic acid (VPA) population pharmacokinetic (PPK) models using an external data set in Chinese adults with epilepsy or after neurosurgery.

METHODS

A total of 384 concentrations from 290 Chinese adults with epilepsy or after neurosurgery were used for external validation. Data on published VPA PPK models were extracted from the literature. Prediction-based diagnostics (such as F20 and F30), simulation-based diagnostics, and Bayesian forecasting were used to evaluate the predictability of models.

RESULTS

The results of prediction-based diagnostics of all models were unsatisfactory. Models B, F, and H showed the best prediction performance in simulation-based diagnostics and Bayesian forecasting, demonstrating superior precision and accuracy. Bayesian forecasting demonstrated significant improvements in the model predictability.

CONCLUSION

The published PPK models showed extensive variation in predictive performance for extrapolation among Chinese adults with epilepsy or after neurosurgery patients. Fixed parameters of Vd and Ka in the PPK modeling of VPA might be the reason for the unsatisfied predictive performance. Bayesian forecasting significantly improved model predictability and may help to individualize VPA dosing.

Determination of Antiepileptics in Biological Samples-A Review

Epilepsy remains a disease that affects many people around the world. With the development of new drugs to treat this condition, the importance of therapeutic drug monitoring continues to rise and remains a challenge for the medical community. This review article explores recent advances in the detection of antiepileptic drugs across various sample types commonly used for drug monitoring, with a focus on their applications and impact. Some of these new methods have proven to be simpler, greener, and faster, making them easier to apply in the context of therapeutic drug monitoring. Additionally, besides the classic use of blood and its derivatives, there has been significant research into the application of alternative matrices due to their ease of sample collection and capacity to reflect drug behavior in blood. These advances have contributed to increasing the efficacy of therapeutic drug monitoring while enhancing its accessibility to the population.

Clinical impact of therapeutic drug monitoring for newer anti-seizure medications in patients with epilepsy: A real-world observation study

BACKGROUND

The clinical value of therapeutic drug monitoring (TDM) for newer anti-seizure medications (ASMs) remains uncertain. This study aimed to assess the impact of newer ASM TDM on clinical decision making in patients with epilepsy.

METHODS

We retrospectively identified all plasma requests for newer ASM level measurement as part of routine clinical management in the outpatient departments of seven medical institutes across Taiwan between September 2016 and May 2019. Data collected from reviewed medical records included clinical and medication details, indications for TDM requests, test results, interpretation, and impact on patient management.

RESULTS

A total of 682 visits with 1051 plasma samples were included. The most frequently analyzed ASMs were levetiracetam (36.1%), oxcarbazepine (18.4%), and lamotrigine (12.0%). Reasons for TDM included poorly controlled seizures (55.3%), concerns about drug-drug interactions (12.3%), and suspicion of drug overdose (10.6%). 68.8% of samples were within the orienting therapeutic range, even for patients with poorly controlled seizures. TDM for non-adherence concerns showed 54.3% below the orienting therapeutic range, while ASM-related adverse events assessment only 8.9% showed levels exceeding the orienting therapeutic range. Following TDM results, 64.2% of cases had medication adjustments, mainly dosage increases. Overall, 55.9% of newer ASM TDM visits showed improved outcomes, including reduced seizures (47.5%) and fewer ASM-related side effects (8.4%).

CONCLUSIONS

These findings suggest that appropriate utilization of TDM for newer ASMs provides clinical benefits in adjunct to complement clinical decision making in the management of epilepsy patients in a real-world clinical setting.

Physiologically-Based Pharmacokinetic Modeling of Total and Unbound Valproic Acid to Evaluate Dosing in Children With and Without Hypoalbuminemia

BACKGROUND AND OBJECTIVE

Valproic acid (VPA) demonstrates nonlinear pharmacokinetics (PK) due to a capacity-limited protein binding, which has potential implications on its total and unbound plasma concentrations, especially during hypoalbuminemia. A physiologically based pharmacokinetic (PBPK) model was developed to assess the nonlinear dose-exposure relationship of VPA with special emphasis on pediatric patients with hypoalbuminemia.

METHODS

A PBPK model was first developed and evaluated in adults using PK-Sim® and MoBi® (v.11) and the scaled to children 1 year and older. The capacity-limited protein binding was characterized by second-order kinetics between VPA and albumin with a 2:1 molar ratio. All drug-specific parameters were informed by literature and optimized using published PK data of VPA. PK simulations were performed in virtual populations with normal and low albumin levels.

RESULTS

The reported concentration-time profiles of total and unbound VPA were adequately predicted by the PBPK model across the age and dose range (3-120 mg/kg). The model was able to characterize the nonlinear PK, as the concentration-dependent fraction unbound (fu) and the related dose-dependent clearance values were well predicted. Simulated steady-state trough concentrations of total VPA were less than dose-proportional and were within the therapeutic drug monitoring range of 50-100 mg/L for doses between 30 and 45 mg/kg per day in children with normal albumin concentrations. However, virtual children with hypoalbuminemia largely failed to achieve the target exposure.

CONCLUSION

The PBPK model helped assess the nonlinear dose-exposure relationship of VPA and the impact of albumin concentrations on the achievement of target exposure.

Lacosamide and Levetiracetam Are Not Toxic to the Developing Mouse Brain

Many antiseizure medications cause apoptotic cell death in developing brains. The newer antiseizure medication lacosamide is increasingly used in neonates and infants. Neurotoxicity of lacosamide and its combination with levetiracetam was studied in neonatal mice. Animals received single or repeat injections of saline, phenobarbital (75mg/kg), lacosamide (20-40mg/kg), levetiracetam (100mg/kg), lacosamide (40mg/kg) + levetiracetam (100mg/kg) and euthanized at 6 to 30 hours. Cells undergoing apoptosis were increased in the brains of phenobarbital-treated animals. Densities of apoptotic profiles following lacosamide and levetiracetam treatment did not differ from saline-treated controls. Findings suggest that lacosamide, levetiracetam and their combination do not cause apoptosis in developing mouse brains. ANN NEUROL 2024;96:812-818.

Association of Lamotrigine Plasma Concentrations With Efficacy and Toxicity in Patients With Epilepsy: A Retrospective Study

BACKGROUND

There is limited evidence to support the currently suggested lamotrigine (LTG) therapeutic reference range of 2.5-15 mg/L for the treatment of seizures. The objective of this study was to evaluate the association of LTG plasma concentrations with the efficacy and toxicity of the treatment in patients with epilepsy.

METHODS

Patients whose LTG plasma concentration was measured between January 2013 and February 2022 were included. Efficacy was defined as seizure freedom for at least 6 months around the time of measured LTG concentration. Toxicity was defined as any LTG-related adverse drug effect documented in each patient's health record or when the reason for measuring the LTG concentration was toxicity. In addition, the dose-concentration relationship of LTG was assessed.

RESULTS

In total, 549 concentrations from 259 patients with epilepsy were included. The most common reasons for therapeutic drug monitoring were suspected inefficacy (39%) and pregnancy (21%). The LTG plasma concentration was not associated with efficacy (adjusted odds ratio = 0.94; 95% confidence interval, 0.85-1.04). The LTG plasma concentration was positively associated with the incidence of toxicity after adjusting for age, sex, and number of antiepileptic drugs (odds ratio = 1.11; 95% confidence interval, 1.04-1.19). The daily dose had a significant linear correlation with the LTG plasma concentration ( P < 0.001).

CONCLUSIONS

The LTG plasma concentration was associated with toxicity, whereas no association with efficacy was found. A reference range of 2.5-10 mg/L may be considered to decrease the risk of toxicity while maintaining similar efficacy. Therapeutic drug monitoring may be useful when LTG-related toxicity is suspected and in cases of pharmacokinetic changes (eg, pregnancy and concomitant use of interacting drugs) that can influence the LTG plasma concentration.

Inhibition of PLA2G4A attenuated valproic acid- induced lysosomal membrane permeabilization and restored impaired autophagic flux: Implications for hepatotoxicity

Valproic acid (VPA) has broad efficacy against several seizures but causes liver injury limiting its prolonged clinical use. Some studies have demonstrated that VPA-induced hepatotoxicity is characterized by microvesicular hepatic steatosis. However, novel detailed mechanisms to explain VPA-induced hepatic steatosis and experimentally rigorously validated protective agents are still lacking. In this study, 8-week-old C57BL/6J mice were gavaged with VPA (500 mg/kg/d) for 4 weeks to establish an in vivo model of VPA-induced chronic liver injury. Quantitative proteomic and non-targeted lipidomic analyses were performed to explore the underlying mechanisms of VPA-induced hepatotoxicity. As a result, VPA-induced hepatotoxicity is associated with impaired autophagic flux, which is attributed to lysosomal dysfunction. Further studies revealed that VPA-induced lysosomal membrane permeabilization (LMP), allows soluble lysosomal enzymes to leak into the cytosol, which subsequently led to impaired lysosomal acidification. A lower abundance of glycerophospholipids and an increased abundance of lysophospholipids in liver tissues of mice in the VPA group strongly indicated that VPA-induced LMP may be mediated by the activation of phospholipase PLA2G4A. Metformin (Met) acted as a potential protective agent attenuating VPA-induced liver dysfunction and excessive lipid accumulation. Molecular docking and cellular thermal shift assays demonstrated that Met inhibited the activity of PLA2G4A by directly binding to it, thereby ameliorating VPA-induced LMP and autophagic flux impairment. In conclusion, this study highlights the therapeutic potential of targeting PLA2G4A-mediated lysosomal dysfunction in VPA-induced hepatotoxicity.

Population pharmacokinetics of valproic acid in children with epilepsy: Implications for dose tailoring when switching from oral syrup to sustained-release tablets

Significant pharmacokinetic (PK) differences exist between different forms of valproic acid (VPA), such as syrup and sustained-release (SR) tablets. This study aimed to develop a population pharmacokinetic (PopPK) model for VPA in children with epilepsy and offer dose adjustment recommendation for switching dosage forms as needed. The study collected 1411 VPA steady-state trough concentrations (Ctrough) from 617 children with epilepsy. Using NONMEM software, a PopPK model was developed, employing a stepwise approach to identify possible variables such as demographic information and concomitant medications. The final model underwent internal and external evaluation via graphical and statistical methods. Moreover, Monte Carlo simulations were used to generate a dose tailoring strategy for typical patients weighting 20-50 kg. As a result, the PK characteristics of VPA were described using a one-compartment model with first-order absorption. The absorption rate constant (ka) was set at 2.64 and 0.46 h-1 for syrup and SR tablets. Body weight and sex were identified as significant factors affecting VPA's pharmacokinetics. The final PopPK model demonstrated acceptable prediction performance and stability during internal and external evaluation. For children taking syrup, a daily dose of 25 mg/kg resulted in the highest probability of achieving the desired target Ctrough, while a dose of 20 mg/kg/day was appropriate for those taking SR tablets. In conclusion, we established a PopPK model for VPA in children with epilepsy to tailor VPA dosage when switching between syrup and SR tablets, aiming to improve plasma VPA concentrations fluctuations.

A Simulation-Based Assessment of Levetiracetam Concentrations Following Fixed and Weight-Based Loading Doses: A Meta-Regression and Pharmacokinetic Modeling Analysis

Current recommendations for refractory status epilepticus (SE) unresponsive to benzodiazepines suggest a loading dose of levetiracetam (LEV) of 60 mg/kg to a maximum of 4500 mg. LEV therapeutic drug monitoring can help guide therapy and is garnering increasing attention. The objective of this study is to simulate the probability of target attainment (PTA) of fixed dose and weight-based loading doses of LEV with respect to established therapeutic target concentrations. Meta-regression of the current literature was performed to evaluate the relationship between intravenous LEV loading dose and seizure cessation in refractory SE patients. A previously published pharmacokinetic model was used to simulate the PTA capacity of competing single intravenous dosing schemes (fixed vs weight-based dosing) to achieve maximum (Cpeak) and 12-h (C12h) plasma concentrations that exceed 12 mg/L. The meta-regression indicated that dosage was not a statistically significant modulator of seizure control at dosages between 20 and 60 mg/kg. Stochastic simulations showed all dosing schemes achieved plasma Cpeak >12 mg/L, but C12h levels were <12 mg/L in subjects over 60 kg with a fixed dose ≤2000 mg or in subjects <60 kg with a weight-based dose <30 mg/kg. Dosages of 40 and 60 mg/kg provided ≥90% PTAs across all weights. Using a weight-based loading dose of 40 mg/kg, up to a suggested maximum of 4500 mg, improves the likelihood of achieving a sustained therapeutic drug concentration after the initial LEV dose, whereas fixed <3000 mg may not achieve the desired concentration before maintenance dosing.

A Cross-Sectional Study Comparing Oxidative Stress in Patients with Epilepsy Treated with Old and New Generation Antiseizure Medications

Background and Objectives: Oxidative stress resulting from a disturbance of the endogenous redox system is suspected in numerous diseases of the central nervous system, including epilepsy. In addition, antiseizure medications (ASMs), especially those of the old generation, may further increase oxidative stress. To evaluate the effects of ASM generation on oxidative stress, we conducted a cross-sectional study in patients with epilepsy treated with old, new, and polytherapy. Materials and Methods: The antioxidant activity of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, as well as the concentrations of malondialdehyde, protein carbonyl, nitrate, nitrite, and glutathione in reduced and oxidized forms, were measured in 49 patients with epilepsy and 14 healthy controls. In addition, the plasma concentrations of ASMs and metabolites of carbamazepine and valproic acid were measured in the patients. Results: Patients with epilepsy showed increased activities of superoxide dismutase and catalase (p < 0.001), concentrations of glutathione disulfide and markers of nitric oxide metabolism (p < 0.001), and decreased activities of glutathione peroxidase, glutathione reductase, glutathione, and nitrite concentrations (p ≤ 0.005) compared to healthy controls. A comparison of ASM generations revealed increased levels of superoxide dismutase and catalase (p ≤ 0.007) and decreased levels of glutathione peroxidase and glutathione reductase (p ≤ 0.01) in patients treated with old ASMs compared to those treated with new generation ASMs. In addition, an increase in protein carbonyl and nitric oxide metabolites (p ≤ 0.002) was observed in patients treated with old generation ASMs compared to those treated with new generation ASMs. Most oxidative stress parameters in patients receiving polytherapy with ASMs were intermediate between the results of patients treated with the old and new generations of ASMs. Conclusions: An increase in oxidative stress markers and modulation of antioxidant enzyme activities was observed in patients with epilepsy compared to controls. The results of our study showed significantly higher oxidative stress in patients treated with old ASMs compared to those treated with new generation ASMs.

Pharmacokinetic variability of everolimus and impact of concomitant antiseizure medications in patients with tuberous sclerosis complex: A retrospective study of therapeutic drug monitoring data in Denmark and Norway

The mTOR-inhibitor everolimus is a precision drug with antiepileptogenic properties approved for treatment of epilepsy in persons with tuberous sclerosis complex (TSC) in combination with other antiseizure medications (ASMs). However, the pharmacokinetic variability of everolimus is scarcely described, and the available information on pharmacokinetic interactions is scarce. The purpose of this study was to investigate pharmacokinetic variability of everolimus in patients with TSC, and the impact of age, sex and comedication. In this retrospective observational study we used anonymized data from medical records of patients with TSC using everolimus in Norway and Denmark, 2012 to 2020. Long-term therapeutic drug monitoring (TDM) identified inter-patient and intra-patient variability. The study included 59 patients, (36 females (61%)), median age 22 (range 3-59 years). Polytherapy was used in 50 patients (85%). The most frequently used ASMs were lamotrigine (n = 21), valproate (n = 17), and levetiracetam (n = 13). Blood concentrations of everolimus were measured in all patients. Pharmacokinetic variability of everolimus between patients was extensive, as demonstrated by a 24-fold variability from minimum-maximum concentration/dose (C/D)-ratios. The coefficient of variation (CV) for intra-patient (n = 59) and inter-patient variability (n = 47, ≥3 measurements) was 40% and 43%, respectively. The C/D-ratio of everolimus was 50% lower in 13 patients (22%) using enzyme-inducing ASMs compared to the 30 patients who did not (0.7 vs 1.4 ng/mL mg, P < .05). Age and sex were not significantly associated with changes in C/D-ratios of everolimus. Long-term TDM identified extensive variability in concentrations over time for everolimus both within and between patients, where comedication with enzyme-inducing ASMs was an important contributing factor. The findings suggest a need for TDM in patients with TSC treated with everolimus.

The incidence and predictive factors of secondary epilepsy in patients with supratentorial brain metastases (st-BMs) after stereotactic radiosurgery: A multicenter retrospective study

OBJECTIVE

To evaluate the incidence and the independent risk factors of SRS-related epilepsy in patients with supratentorial brain metastases (st-BMs), providing evidences for prevention or reduction secondary epilepsy after SRS.

METHODS

Patients with st-BMs from four gamma knife centers who developed secondary epilepsy after SRS were retrospectively studied between January 1, 2017 and June 31, 2023. The incidence and clinical characteristics of the patients with secondary epilepsy were analyzed. The predictive role of baseline clinical-demographic variables was evaluated according to univariate and multivariate logistic regression model. The impact of secondary epilepsy on patients' OS was evaluated as well by log-rank test.

RESULTS

11.3 % (126/1120) of the patients with totally 158 st-BMs experienced secondary epilepsy after SRS in median 21 days. 61.9 % (78/126) of the patients experienced simple partial seizures. 91.3 % (115/126) patients achieved good seizure control after received 1-2 kinds of AEDs for median 90 days, while 7.1 % (9/126) of the patients suffered from refractory epilepsy. Patients had higher risk of secondary epilepsy if the tumor located in cortex and/or hippocampus, peri-tumor edema larger than 20.3 cm3 before SRS, had epilepsy history, and failed to receive bevacizumab prior to SRS. There was no difference in the OS of patients who experience secondary epilepsy or not after SRS.

CONCLUSIONS

The incidence of SRS-related secondary epilepsy is 11.3 % in patients with st-BMs in this retrospective study. The risk of secondary epilepsy is higher in patients with st-BM located in cortex and/or hippocampus area, peri-tumor edema larger than 20.3 cm3 before SRS, and epilepsy history. Bevacizumab is suggested prior to SRS therapy, as it could be used for the control of peri-tumor edema and SRS-related damage, hence reduce the risk of secondary epilepsy. However, whether or not patients suffered from secondary epilepsy after SRS does not affect their OS.

Innovative LC-MS/MS method for therapeutic drug monitoring of fenfluramine and cannabidiol in the plasma of pediatric patients with epilepsy

We present a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying fenfluramine (FFA), its active metabolite norfenfluramine (norFFA), and Epidyolex®, a pure cannabidiol (CBD) oral solution in plasma. Recently approved by the EMA for the adjunctive treatment of refractory seizures in patients with Dravet and Lennox-Gastaut syndromes aged above 2 years, FFA and CBD still do not have established therapeutic blood ranges, and thus need careful drug monitoring to manage potential pharmacokinetic and pharmacodynamic interactions. Our method, validated by ICH guidelines M10, utilizes a rapid extraction protocol from 100 µL of human plasma and a reversed-phase C-18 HPLC column, with deuterated internal standards. The Thermofisher Quantiva triple-quadrupole MS coupled with an Ultimate 3000 UHPLC allowed multiple reaction monitoring detection, ensuring precise analyte quantification. The assay exhibited linear responses across a broad spectrum of concentrations: ranging from 1.64 to 1000 ng/mL for both FFA and CBD, and from 0.82 to 500 ng/mL for norFFA. The method proves accurate and reproducible, free from matrix effect. Additionally, FFA stability in plasma at 4 °C and -20 °C for up to 7 days bolsters its clinical applicability. Plasma concentrations detected in patients samples, expressed as mean ± standard deviation, were 0.36 ± 0.09 ng/mL for FFA, 19.67 ± 1.22 ng/mL for norFFA. This method stands as a robust tool for therapeutic drug monitoring (TDM) of FFA and CBD, offering significant utility in assessing drug-drug interactions in co-treated patients, thus contributing to optimized patient care in complex therapeutic scenarios.

UGT1A4*3 polymorphism influences serum concentration and therapeutic effect of lamotrigine for epilepsy treatment: A meta-analysis

BACKGROUND

Lamotrigine as a broad-spectrum antiepileptic drug, is widely applied and its clinical efficacy is highly recognized. However, significant differences are observed in blood drug concentration of lamotrigine among individuals, which may have an impact on its efficacy. UGT1A4 is the main metabolic enzyme. However, it was inconsistent for the influence of UGT1A4 genetic polymorphism on concentration and efficacy of lamotrigine therapy. This study aimed to evaluate the influences of UGT1A4*3 genetic polymorphisms on lamotrigine concentration and therapeutic effect through meta-analysis.

METHODS

The literature search was conducted in Medline, Embase, PubMed, Web of Science, Wan Fang Database, China National Knowledge Infrastructure, China Science and Technology Journal Database until January 2024. The primary outcome included the mean serum concentration, concentration-to-dose-ratio by body weight (CDR), or efficacy related to different UGT1A4*3 genotype for lamotrigine therapy. Data were collected to access the Mean Difference or odds ratio with 95% confidence interval. Meta-analysis was performed by RevMan 5.2.

RESULTS

A total of eleven studies were enrolled. The meta-analysis for mean serum concentration of lamotrigine showed no significant difference between patients carrying TT genotypes and TG and GG genotypes group (MD: 0.12, 95% [-0.35, 0.58], P = 0.62). There was significant difference in CDR (MD: 0.49, 95% [0.03, 0.94], P = 0.04) and therapeutic efficacy (OR: 7.18, 95% [4.01, 12.83], P<0.00001) of lamotrigine, however no significant difference was found in subgroup analysis of CDR of children (MD: 0.03, 95% [-0.35, 0.42], P = 0.87) between patients carrying TT genotypes and TG and GG genotypes group.

CONCLUSIONS

Polymorphism of UGT1A4*3 influenced the CDR and therapeutic efficacy of lamotrigine for antiepileptic therapy. Genotype analysis provided reference for personalized medication in the future. However, more high-quality evidences are necessary for precise and definitive conclusion.

Antibiotics, Analgesic Sedatives, and Antiseizure Medications Frequently Used in Critically Ill Neonates: A Narrative Review

Antibiotic, analgesic sedative, and antiseizure medications are among the most commonly used medications in preterm/sick neonates, who are at high risk of nosocomial infections, central nervous system complications, and are exposed to numerous painful/stressful procedures. These severe and potentially life-threatening complications may have serious short- and long-term consequences and should be prevented and/or promptly treated. The reported variability in the medications used in neonates indicates the lack of adequate neonatal studies regarding their effectiveness and safety. Important obstacles contributing to inadequate studies in preterm/sick infants include difficulties in obtaining parental consent, physicians' unwillingness to recruit preterm infants, the off-label use of many medications in neonates, and other scientific and ethical concerns. This review is an update on the use of antimicrobials (antifungals), analgesics (sedatives), and antiseizure medications in neonates, focusing on current evidence or knowledge gaps regarding their pharmacokinetics, indications, safety, dosage, and evidence-based guidelines for their optimal use in neonates. We also address the effects of early antibiotic use on the intestinal microbiome and its association with long-term immune-related diseases, obesity, and neurodevelopment (ND). Recommendations for empirical treatment and the emergence of pathogen resistance to antimicrobials and antifungals are also presented. Finally, future perspectives on the prevention, modification, or reversal of antibiotic resistance are discussed.

The impact of pregnancy on the pharmacokinetics of antiseizure medications: A systematic review and meta-analysis of data from 674 pregnancies

OBJECTIVE

Increasing evidence suggests that the physiological changes of pregnancy may impact pharmacokinetics of antiseizure medications (ASM), and this may affect treatment outcomes. The aim of this study was to quantify the pregnancy impact on the ASM pharmacokinetics.

METHODS

A systematic literature search was conducted in PubMed/EMBASE in November 2022 and updated in August 2023 for studies comparing levels of ASM in the same individuals during pregnancy and in the preconception/postpartum period. Alteration ratios between the 3rd trimester and baseline were estimated. We also performed a random-effects meta-analysis calculating between-timepoint differences in mean differences (MDs) and 95% confidence intervals (95%CIs) for dose-adjusted plasma concentrations (C/D ratios). Study quality was assessed using the ClinPK guidelines.

RESULTS

A total of 65 studies investigating 15 ASMs in 674 pregnancies were included. The largest differences were reported for lamotrigine, oxcarbazepine and levetiracetam (alteration ratio 0.42, range 0.07-2.45, 0.42, range 0.08-0.82 and 0.52, range 0.04-2.77 respectively): accordingly, C/D levels were lower in the 3rd trimester for lamotrigine, levetiracetam and the main oxcarbazepine metabolite monohydroxycarbazepine (MD = -12.33 × 10-3, 95%CI = -16.08 to -8.58 × 10-3 (μg/mL)/(mg/day), p < 0.001, MD = -7.16 (μg/mL)/(mg/day), 95%CI = -9.96 to -4.36, p < 0.001, and MD = -4.87 (μg/mL)/(mg/day), 95%CI = -9.39 to -0.35, p = 0.035, respectively), but not for oxcarbazepine (MD = 1.16 × 10-3 (μg/mL)/(mg/day), 95%CI = -2.55 to 0.24 × 10-3, p = 0.10). The quality of studies was acceptable with an average rating score of 11.5.

CONCLUSIONS

Data for lamotrigine, oxcarbazepine (and monohydroxycarbazepine) and levetiracetam demonstrate major changes in pharmacokinetics during pregnancy, suggesting the importance of therapeutic drug monitoring to assist clinicians in optimizing treatment outcomes.

Optimizing vancomycin therapeutic drug monitoring compliance in pediatric oncology: towards personalized medication management

Aim: Vancomycin, a crucial treatment for Gram-positive bacteria, necessitates therapeutic drug monitoring (TDM) to prevent treatment failures. We investigated the healthcare professional's compliance toward TDM of vancomycin recommendations and follow-up levels. Materials & methods: We collected data from 485 patients who received vancomycin in the Children's Cancer Hospital Egypt 57357 medical records system (Cerner) over 4 months, from January to April 2020. Results: Our data shows that only 54% of patients had TDM requests from healthcare professionals for the total patients who received vancomycin treatment. The healthcare professionals' compliance with the recommendations was 91.7%, while the follow-up levels were 66.7%. Conclusion: While overall adherence to recommendations is strong, enhancing compliance with follow-up levels remains a priority for improvement.

Signal interference between drugs and metabolites in LC-ESI-MS quantitative analysis and its evaluation strategy

Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS) is a widely utilized technique for in vivo pharmaceutical analysis. Ionization interference within electrospray ion source, occurring between drugs and metabolites, can lead to signal variations, potentially compromising quantitative accuracy. Currently, method validation often overlooks this type of signal interference, which may result in systematic errors in quantitative results without matrix-matched calibration. In this study, we conducted an investigation using ten different groups of drugs and their corresponding metabolites across three LC-ESI-MS systems to assess the prevalence of signal interference. Such interferences can potentially cause or enhance nonlinearity in the calibration curves of drugs and metabolites, thereby altering the relationship between analyte response and concentration for quantification. Finally, we established an evaluation scheme through a step-by-step dilution assay and employed three resolution methods: chromatographic separation, dilution, and stable labeled isotope internal standards correction. The above strategies were integrated into the method establishment process to improve quantitative accuracy.

Clinical Pharmacokinetics and Pharmacodynamics of Letermovir in Allogenic Hematopoietic Cell Transplantation

Letermovir is a newly developed antiviral agent used for the prophylaxis of human cytomegalovirus infections in patients undergoing allogeneic hematopoietic cell transplantation. This novel anti-cytomegalovirus drug, used for the prophylaxis of cytomegalovirus reactivation until approximately 200 days after transplantation, effectively reduces the risk of clinically significant cytomegalovirus infection. No human counterpart exists for the terminase complex; letermovir is virus specific and lacks some toxicities previously observed with other anti-cytomegalovirus drugs, such as cytopenia and nephrotoxicity. The absolute bioavailability of letermovir in healthy individuals is estimated to be 94% based on a population-pharmacokinetic analysis. In contrast, oral administration of letermovir to patients undergoing hematopoietic cell transplantation results in lower exposure than that in healthy individuals. Renal or hepatic impairment does not influence the intrinsic clearance of letermovir. Co-administration of letermovir may alter the plasma concentrations of other drugs, including itself, as it acts as a substrate and inhibitor/inducer of several drug-metabolizing enzymes and transporters. In particular, attention should be paid to the drug-drug interactions between letermovir and calcineurin inhibitors or azole antifungal agents, which are commonly used in patients undergoing hematopoietic cell transplantation. This article reviews and summarizes the clinical pharmacokinetics and pharmacodynamics of letermovir, focusing on patients undergoing hematopoietic cell transplantation, healthy individuals, and specific patient subsets.

An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure (RMP) for the quantification of phenobarbital in human serum and plasma

OBJECTIVES

Phenobarbital serves as an antiepileptic drug (AED) and finds application in the treatment of epilepsy either as monotherapy or adjunctive therapy. This drug exhibits various pharmacodynamic properties that account for its beneficial effects as well as potential side effects. Accurate measurement of its concentration is critical for optimizing AED therapy through appropriate dose adjustments. Therefore, our objective was to develop and validate a new reference measurement procedure (RMP) for the accurate quantification of phenobarbital levels in human serum and plasma.

METHODS

A sample preparation protocol based on protein precipitation followed by a high dilution step was established in combination with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using a C8 column to separate target analytes from known and unknown interferences. Assay validation and determination of measurement uncertainty were performed based on current guidelines. Selectivity and Specificity were assessed using spiked serum and plasma samples; to investigate possible matrix effects (MEs) a post-column infusion experiment and a comparison of standard line slopes was performed. Precision and accuracy were determined within a multiday precision experiment.

RESULTS

The RMP was shown to be highly selective and specific, with no evidence of matrix interferences. It can be used to quantify phenobarbital in the range of 1.92 to 72.0 μg/mL. Intermediate precision was less than 3.2 %, and repeatability coefficient of variation (CV) ranged from 1.3 to 2.0 % across all concentration levels. The relative mean bias ranged from -3.0 to -0.7 % for native serum levels, and from -2.8 to 0.8 % for Li-heparin plasma levels. The measurement uncertainties (k=1) for single measurements and target value assignment were 1.9 to 3.3 % and 0.9 to 1.6 %, respectively.

CONCLUSIONS

A novel LC-MS/MS-based candidate RMP for the quantification of phenobarbital in human serum and plasma is presented which can be used for the standardization of routine assays and the evaluation of clinically relevant samples.

Chronic Treatment with Oxcarbazepine Attenuates Its Anticonvulsant Effect in the Maximal Electroshock Model in Mice

The objective of this study was to assess the impact of acute and chronic treatment with oxcarbazepine on its anticonvulsant activity, neurological adverse effects, and protective index in mice. Oxcarbazepine was administered in four protocols: once or twice daily for one week (7 × 1 or 7 × 2) and once or twice daily for two weeks (14 × 1 or 14 × 2). A single dose of the drug was employed as a control. The anticonvulsant effect was evaluated in the maximal electroshock test in mice. Motor and long-term memory impairment were assessed using the chimney test and the passive avoidance task, respectively. The concentrations of oxcarbazepine in the brain and plasma were determined via high-performance liquid chromatography. Two weeks of oxcarbazepine treatment resulted in a significant reduction in the anticonvulsant (in the 14 × 1; 14 × 2 protocols) and neurotoxic (in the 14 × 2 schedule) effects of this drug. In contrast, the protective index for oxcarbazepine in the 14 × 2 protocol was found to be lower than that calculated for the control. No significant deficits in memory or motor coordination were observed following repeated administration of oxcarbazepine. The plasma and brain concentrations of this anticonvulsant were found to be significantly higher in the one-week protocols. Chronic treatment with oxcarbazepine may result in the development of tolerance to its anticonvulsant and neurotoxic effects, which appears to be dependent on pharmacodynamic mechanisms.

New data-driven method to predict the therapeutic indication of redeemed prescriptions in secondary data sources: a case study on antiseizure medications users aged ≥65 identified in Danish registries

OBJECTIVES

We aimed to develop a new data-driven method to predict the therapeutic indication of redeemed prescriptions in secondary data sources using antiepileptic drugs among individuals aged ≥65 identified in Danish registries.

DESIGN

This was an incident new-user register-based cohort study using Danish registers.

SETTING

The study setting was Denmark and the study period was 2005-2017.

PARTICIPANTS

Participants included antiepileptic drug users in Denmark aged ≥65 with a confirmed diagnosis of epilepsy.

PRIMARY AND SECONDARY OUTCOME MEASURES

Sensitivity served as the performance measure of the algorithm.

RESULTS

The study population comprised 8609 incident new users of antiepileptic drugs. The sensitivity of the algorithm in correctly predicting the therapeutic indication of antiepileptic drugs in the study population was 65.3% (95% CI 64.4 to 66.2).

CONCLUSIONS

The algorithm demonstrated promising properties in terms of overall sensitivity for predicting the therapeutic indication of redeemed antiepileptic drugs by older individuals with epilepsy, correctly identifying the therapeutic indication for 6 out of 10 individuals using antiepileptic drugs for epilepsy.