Oxcarbazepine: a review

The Effect of Neuropsychiatric Drugs on the Oxidation-Reduction Balance in Therapy

The effectiveness of available neuropsychiatric drugs in the era of an increasing number of patients is not sufficient, and the complexity of neuropsychiatric disease entities that are difficult to diagnose and therapeutically is increasing. Also, discoveries about the pathophysiology of neuropsychiatric diseases are promising, including those initiating a new round of innovations in the role of oxidative stress in the etiology of neuropsychiatric diseases. Oxidative stress is highly related to mental disorders, in the treatment of which the most frequently used are first- and second-generation antipsychotics, mood stabilizers, and antidepressants. Literature reports on the effect of neuropsychiatric drugs on oxidative stress are divergent. They are starting with those proving their protective effect and ending with those confirming disturbances in the oxidation-reduction balance. The presented publication reviews the state of knowledge on the role of oxidative stress in the most frequently used therapies for neuropsychiatric diseases using first- and second-generation antipsychotic drugs, i.e., haloperidol, clozapine, risperidone, olanzapine, quetiapine, or aripiprazole, mood stabilizers: lithium, carbamazepine, valproic acid, oxcarbazepine, and antidepressants: citalopram, sertraline, and venlafaxine, along with a brief pharmacological characteristic, preclinical and clinical studies effects.

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.

Application of Northern Goshawk Back-Propagation Artificial Neural Network in the Prediction of Monohydroxycarbazepine Concentration in Patients with Epilepsy

INTRODUCTION

A northern goshawk back-propagation artificial neural network (NGO-BPANN) model was established to predict monohydroxycarbazepine (MHD) concentration in patients with epilepsy.

METHODS

The data were collected from 108 Han Chinese patients with epilepsy on oxcarbazepine monotherapy. The results of 14 genotype variates were selected as the input layer in the first BPANN model, and the variables that had a more significant impact on the plasma concentration of MHD were retained. With demographic characteristics and clinical laboratory test results, the genotypes of SCN1A rs2298771 and SCN2A rs17183814 were used to construct the BPANN model. The BPANN model was comprehensively validated and used to predict the MHD plasma concentration of five patients with epilepsy in our hospital.

RESULTS

The model demonstrated favorable fitness metrics, including a mean squared error of 0.00662, a gradient magnitude of 0.00753, an absence of validation tests amounting to zero, and a correlation coefficient of 0.980. Sex, BMI, and the genotype SCN1A rs2298771 were ranked highest by the absolute mean impact value (MIV), which is primarily associated with the concentration of MHD. The test group exhibited a range of - 20.84% to 31.03% bias between the predicted and measured values, with a correlation coefficient of 0.941 between the two. With BPANN, the MHD nadir concentration could be predicted precisely.

CONCLUSION

The NGO-BPANN model exhibits exceptional predictive capability and can be a practical instrument for forecasting MHD concentration in patients with epilepsy.

CLINICAL TRIAL REGISTRATION

www.chiCTR-OOC-17012141 .

Risk assessment of arrhythmias related to three antiseizure medications: a systematic review and single-arm meta-analysis

Objective

Antiseizure medications (ASMs) are first line therapy for seizure disorders. Their effects on arrhythmias, especially the risk of arrhythmias associated with lacosamide (LCM), levetiracetam (LEV), and perampanel (PER), have been intensely investigated.

Methods

We searched four databases (PubMed, EMBASE, Cochrane Library, and Web of Science) until August 6, 2023. We used a common effects model and reported data as pooled incidence with 95% CIs. Meta-analyses were conducted to elucidate the risk of arrhythmias with different drugs, and Egger's regression was performed to detect publication bias analysis.

Results

We included 11 clinical trials with 1,031 participants. The pooled incidence of arrhythmias in the LEV group was 0.005 (95% CI: 0.001-0.013), while it was 0.014 in the LCM group (95% CI: 0.003-0.030). Publication bias analyses indicated no significant bias in the LEV group (t = 0.02, df = 4, p-value = 0.9852) but a significant bias in the LCM group (t = 5.94, df = 3, p-value = 0.0095). We corrected for this bias in the LCM group using the trim-and-fill method, which yielded a similar pooled incidence of 0.0137 (95% CI: 0.0036-0.0280), indicating good reliability. Due to insufficient studies, we could not conduct a meta-analysis for PER, and we analyzed them in our systematic review.

Conclusion

The use of LCM significantly elevated the risk of arrhythmias, while LEV had non-significant arrhythmogenic effects. As for the arrhythmogenic effects of PER, more clinical trials are needed in the future.

Potential impact of mesenchymal stem cells on nephrotoxicity induced by gamma irradiation and antiepileptic drugs cotherapy in rats

The goal of this study was to assess the influence of bone marrow-derived mesenchymal stem cells (BM-MSCs) on the nephrotoxicity induced by fractionated doses of gamma irradiation (Rad) and the cotherapy of levetiracetam and oxcarbazepine in male rats. Adult rats were randomly divided into four groups. Group I: Control, Group II: antiepileptic drugs (AEDs), Group III: AEDs +Rad and Group IV: AEDs + Rad + MSCs. Rats treated with AEDs and exposed to fractionated doses of γ-irradiation displayed a discernible increase in serum urea, creatinine, kidney injury marker, kidney malondialdehyde, transforming growth factor beta (TGF-β) and the relative expression of Smad3 along with a decrease in the relative expression of Smad7 and glutathione level. Alternatively, groups treated with BM-MSCs with AEDs and Rad showed a substantial modification in the majority of the evaluated parameters and looked to be successful in reducing the hazards of the combination therapy of AEDs and radiation. The reno-histopathological study supports the biochemical analysis. In conclusion, BM-MSCs exhibited therapeutic potential against nephrotoxicity induced by fractionated doses of γ-irradiation and AEDs. The outcome was brought about by the downregulation of the TGF-β/Smad pathway. BM-MSCs might be suggested as a valuable therapeutic strategy to overcome kidney injury induced by gamma irradiation during AEDs cotherapy.

Analysis of clinical features of oxcarbazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis

Background

Stevens-Johnson syndrome (SJS) is considered a hypersensitivity syndrome affecting the skin and mucous membranes. It has been reported that an anticonvulsant drug, oxcarbazepine, may cause Stevens-Johnson syndrome and toxic epidermal necrolysis (TEN). However, the clinical features of oxcarbazepine-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) remain ambiguous. This article aims to explore the clinical features of SJS/TEN.

Methods

Systematic searches of several Chinese and English databases were conducted for case reports published on PubMed, EMBASE, Web of Science, MEDLINE, CNKI from January 1, 2007 to March 1, 2023.

Results

A total of seventeen patients (10 males and 7 females) were included in this study, including nine adult patients and eight pediatric patients. The results showed that males seem to have a higher prevalence of SJS/TEN than females, and SJS/TEN usually occurs within 2 weeks after administration of oxcarbazepine (OXC). The main clinical manifestations among the included patients were rashes or maculopapules (17 cases, 100%), fever (11 cases, 64.7%), mucosal lesions (15 cases, 88.2%), conjunctivitis with/without ocular discharge (12 cases, 70.6%), and blisters (12 cases, 70.6%). After stopping OXC or switching to other drugs that treat primary disease as well as treatment with IVIG, glucocorticoid, anti-allergy, and fluid replacement, eight of the included patients recovered completely, and another eight of the included patients reported symptomatic improvement, while the prognosis of one of the included patients was not reported.

Conclusion

Diverse clinical signs and symptoms of SJS/TEN might result in misinterpretation and delayed diagnosis. It should be identified and treated immediately to avoid significant consequences and potentially jeopardize patients' lives.

Antiseizure Medications for the Prophylaxis of Migraine during the Anti- CGRP Drugs Era

Migraine and epilepsy are fundamentally distinct disorders that can frequently coexist in the same patient. These two conditions significantly differ in diagnosis and therapy but share some widely- used preventive treatments. Antiseizure medications (ASMs) are the mainstay of therapy for epilepsy, and about thirty different ASMs are available to date. ASMs are widely prescribed for other neurological and non-neurological conditions, including migraine. However, only topiramate and valproic acid/valproate currently have an indication for migraine prophylaxis supported by high-quality evidence. Although without specifically approved indications and with a low level of evidence or recommendation, several other ASMs are used for migraine prophylaxis. Understanding ASM antimigraine mechanisms, including their ability to affect the pro-migraine calcitonin gene-related peptide (CGRP) signaling pathway and other pathways, may be instrumental in identifying the specific targets of their antimigraine efficacy and may increase awareness of the neurobiological differences between epilepsy and migraine. Several new ASMs are under clinical testing or have been approved for epilepsy in recent years, providing novel potential drugs for migraine prevention to enrich the treatment armamentarium and drugs that inhibit the CGRP pathway.

Levetiracetam versus Oxcarbazepine as monotherapy in newly diagnosed focal epilepsy: A systematic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of Levetiracetam (LEV) and Oxcarbazepine (OXC) as monotherapy for the treatment of newly diagnosed focal epilepsy.

METHODS

We searched PubMed, Cochrane Library, EMBASE, and Google Scholar from January 1, 2000 to May 11, 2022, with no language restrictions along with The ClinicalTrials.gov website and the WHO International Controlled Trials Registry platforms. We pooled the risk ratio (RR) and corresponding 95% confidence interval (95% CI) for the efficacy and safety outcomes. The quality of included trials was assessed using the Cochrane Collaboration's tool.

RESULTS

Two RCTs included a total of 574 newly diagnosed focal epilepsy patients (the LEV group [282 patients] and the OXC group [292 patients]). LEV group when compared with the OXC group had no significant difference in the pooled estimate of seizure freedom at week 24. (RR: 0.81; 95% CI: 0.62-1.05, p = .11). Similarly, there was no significant difference in the pooled estimate of withdrawal due to adverse events (AEs) (RR: 0.87; 95% CI: 0.34-2.23, p = .77). The commonly reported AEs in both trials were dizziness, headache, rash, somnolence, and nasopharyngitis with zero medication-related death and few serious AEs.

CONCLUSIONS

LEV is noninferior to OXC in terms of seizure freedom at week 24 and treatment withdrawal rate due to AEs among adults but long-term treatment data is still missing. Future multicentric double-blinded RCTs and real-world studies are of great need.

Efficacy comparison of oxcarbazepine and levetiracetam monotherapy among patients with newly diagnosed focal epilepsy in China: A multicenter, open-label, randomized study

Aims

This multicenter, open‐label, randomized study (Registration No. ChiCTR‐OCH‐14004528) aimed to compare the efficacy and effects of oxcarbazepine (OXC) with levetiracetam (LEV) as monotherapies on patient quality of life and mental health for patients with newly diagnosed focal epilepsy from China.

Methods

Patients with newly diagnosed focal epilepsy who had experienced 2 or more unprovoked seizures at greater than a 24‐h interval during the previous year were recruited. Participants were randomly assigned to the OXC group or LEV group. Efficacy, safety, quality of life, and mental health were evaluated over 12‐week and 24‐week periods.

Results

In total, we recruited 271 newly diagnosed patients from 23 centers. Forty‐four patients were excluded before treatment for reasons. The rate of seizure freedom of OXC was significantly superior to that of LEV at 12 weeks and 24 weeks (p < 0.05). The quality of life (except for the seizure worry subsection) and anxiety scale scores also showed significant differences from before to after treatment in the OXC and LEV groups.

Conclusions

OXC monotherapy may be more effective than LEV monotherapy in patients with newly diagnosed focal epilepsy. Both OXC and LEV could improve the quality of life and anxiety state in adult patients with focal epilepsy.

Complex Regional Pain Syndrome: Practical Diagnostic and Treatment Guidelines, 5th Edition

There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated multifactorial disease remains low (with some notable exceptions; e.g., the recent work on the dorsal root ganglion stimulation). The semi-systematic (though in some cases narrative) approach to review is necessary so that we might treat our patients while waiting for "better research." This semi-systematic review was conducted by experts in the field, (deliberately) some of whom are promising young researchers supplemented by the experience of "elder statesman" researchers, who all mention the system they have used to examine the literature. What we found is generally low- to medium-quality research with small numbers of subjects; however, there are some recent exceptions to this. The primary reason for this paucity of research is the fact that this is a rare disease, and it is very difficult to acquire a sufficient sample size for statistical significance using traditional statistical approaches. Several larger trials have failed, probably due to using the broad general diagnostic criteria (the "Budapest" criteria) in a multifactorial/multi-mechanism disease. Responsive subsets can often be identified in these larger trials, but not sufficient to achieve statistically significant results in the general diagnostic grouping. This being the case the authors have necessarily included data from less compelling protocols, including trials such as case series and even in some instances case reports/empirical information. In the humanitarian spirit of treating our often desperate patients with this rare syndrome, without great evidence, we must take what data we can find (as in this work) and tailor a treatment regime for each patient.

Oxcarbazepine induces mitotic catastrophe and apoptosis in NRK-52E proximal tubular cells

Certain medicines including anticancer drugs, NSAIDs and antiepileptic drugs are known to cause drug-induced nephropathy. For example, antiepileptic drugs such as carbamazepine (CBZ) and valproic acid have been reported to cause damage to the proximal tubular cells. Although there has been a great deal of research concerning the nephrotoxicity of CBZ, little is known about that of oxcarbazepine (OXC), a derivative of CBZ. To investigate the molecular mechanism underlying renal proximal tubular cell death caused by OXC, we examined alterations in the gene expression profile of NRK-52E proximal tubular cells during OXC exposure. DNA microarray analysis revealed that the levels of genes related to mitotic processes including chromosomal and cytoplasmic segregation, progression to G2/M phase, and formation of the mitotic spindle are increased after exposure to 50 μM OXC for 6 h. Cell cycle analysis by flow cytometry showed that OXC at concentrations between 25 and 100 μM induces G2/M arrest. We also found that OXC significantly increases histone H3 phosphorylation, indicative of mitotic cells. These results imply that OXC induces cell cycle arrest at the mitotic phase. Immunofluorescence analysis showed monopolar spindles, which are formed in response to centrosome separation defects, in OXC-treated cells. We also show that OXC suppresses the phosphorylation of PLK1, which is involved not only in the activation of the kinesin family of motor proteins for centrosome separation and bipolar spindle assembly, but also in the cleavage of centrosomal proteins. Thus, our results indicate that OXC inhibits centrosome separation by reducing the activation of PLK1, which leads to the formation of an abnormal spindle and induces mitotic catastrophe and apoptosis in NRK-52E cells.

Population pharmacokinetic model development and its relationship with adverse events of oxcarbazepine in adult patients with epilepsy

This study aimed to develop a pharmacokinetic (PK) model of oxcarbazepine (OXC) and analyse the relationship between monohydroxylated derivative (MHD), an active metabolite of OXC, and the adverse events of OXC. We obtained 711 OXC samples from 618 patients with epilepsy who were enrolled in the Epilepsy Registry Cohort of Seoul National University Hospital from February 2011 to January 2014. The plasma PK model was developed using a nonlinear mixed-effect modelling method with NONMEM (ver 7.3). A one-compartment model with a first-order absorption model and proportional residual error adequately described the MHD concentration–time profiles. The only covariate incorporated for CL/F and V/F was body weight. Of the 447 patients analysed, 28 (6.26%) had dose-related adverse events (DRAEs), which were dizziness, somnolence, headache, and diplopia. For DRAE occurrence, the cut-off values of the MHD trough and AUC were 12.27 mg/L (specificity 0.570, sensitivity 0.643) and 698.5 mg h/L (specificity, sensitivity 0.571), respectively. Multivariate analysis showed the sole dizziness symptom was significantly associated with both the MHD trough and the AUC (p = 0.013, p = 0.038, respectively). We newly developed a population PK model using sparse sampling data from patients with epilepsy, and the model better reflects the actual clinical situation.

HLA Risk Alleles in Aromatic Antiepileptic Drug-Induced Maculopapular Exanthema

To characterize human leukocyte antigen (HLA) loci as risk factors in aromatic antiepileptic drug-induced maculopapular exanthema (AED-MPE). A case-control study was performed to investigate HLA loci involved in AED-MPE in a southern Han Chinese population. Between January 2007 and June 2019, 267 patients with carbamazepine (CBZ), oxcarbazepine (OXC), or lamotrigine (LTG) associated MPE and 387 matched drug-tolerant controls from six centers were enrolled. HLA-A/B/C/DRB1 genotypes were determined using sequence-based typing. Potential risk alleles were validated by meta-analysis using data from different populations and in silico analysis of protein-drug interactions. HLA-DRB1*04:06 was significantly associated with OXC-MPE (p = 0.002, p _c = 0.04). HLA-B*38:02 was associated with CBZ-MPE (p = 0.03). When pooled, HLA-A*24:02, HLA-A*30:01, and HLA-B*35:01 additionally revealed significant association with AED-MPE. Logistic regression analysis showed a multiplicative interaction between HLA-A*24:02 and HLA-B*38:02 in CBZ-MPE. Meta-analysis of data from different populations revealed that HLA-24*:02 and HLA-A*30:01 were associated with AED-MPE (p = 0.02 and p = 0.04, respectively). In silico analysis of protein-drug interaction demonstrated that HLA-A*24:02 and HLA-A*30:01 had higher affinities with the three aromatic AEDs than the risk-free HLA-A allele. HLA-DRB1*04:06 showed relatively specific high affinity with S-monohydroxy derivative of OXC. HLA-DRB1*04:06 is a specific risk allele for OXC-induced MPE in the Southern Han Chinese. HLA-A*24:02, possibly HLA-A*30:01, are common risk factors for AED-MPE. The multiplicative risk potential between HLA-A*24:02 and HLA-B*38:02 suggests that patients with two risk alleles are at greater risk than those with one risk allele. Inclusion of these HLA alleles in pre-treatment screening would help estimating the risk of AED-MPE.

Toward a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny - part I: which parameters from human studies are most relevant for toxicological assessments?

The 2018 European Food Safety Authority/European Chemicals Agency Guidance on the Identification of Endocrine Disruptors lacks clarity on how the presence or absence of substance-induced maternal thyroid hormone imbalance, or the potential for subsequent deleterious consequences in child neurodevelopment, should be established by toxicological assessments. To address these uncertainties, this narrative review evaluates human evidence on how altered maternal thyroid function may be associated with child neurodevelopmental outcomes; and seeks to identify parameters in human studies that appear most relevant for toxicological assessments. Serum levels of free thyroxine (fT4) and thyroid stimulating hormone (TSH) are most frequently measured when assessing thyroid function in pregnant women, whereas a broad spectrum of neurodevelopmental parameters is used to evaluate child neurodevelopment. The human data confirms an association between altered maternal serum fT4 and/or TSH and increased risk for child neurodevelopmental impairment. Quantitative boundaries of effects indicative of increased risks need to be established. Moreover, it is unknown if altered serum levels of total T4, free or total triiodothyronine, or parameters unrelated to serum thyroid hormones might be more relevant indicators of such effects. None of the human studies established a link between substance-mediated liver enzyme induction and increased serum thyroid hormone clearance, let alone further to child neurodevelopmental impairment. This review identifies research needs to contribute to the development of toxicity testing strategies, to reliably predict whether substances have the potential to impair child neurodevelopment via maternal thyroid hormone imbalance.

Prenatal exposure to oxcarbazepine increases hippocampal apoptosis in rat offspring

This study assessed apoptosis in the offspring of rats exposed to oxcarbazepine (OXC) from day 7 to 15 of gestation. Three groups of pregnant Wistar rats were used: 1) Control, treated with saline solution; 2) treated with 100 mg/kg OXC; 3) treated with 100 mg/kg of carbamazepine (CBZ, as a positive control for apoptosis); the route of administration was intragastric. Apoptosis was detected at three postnatal ages using the TUNEL technique in the CA1, and CA3 regions of the hippocampus and in the dentate gyrus (DG); neurogenesis was assessed in the DG using an antibody against doublecortin. The litter characteristics were recorded. OXC increased apoptosis in all regions (p < 0.01) at the three ages evaluated. Lamination disruption occurred in CA1 and CA3 due to the neuron absence and to ectopic neurons; there were also malformations in the dorsal lamina of the DG in 38% and 25% of the pups born from rats treated with OXC and CBZ respectively. CBZ also increased apoptosis. No clear effect on neurogenesis in the DG was observed. The size of the litter was smaller (p < 0.01) in the experimental groups. Nineteen-day OXC fetuses had low weight (p < 0.01), but 21 and 30 postnatal days old CBZ and OXC pups were overweight (p < 0.01). The results demonstrate that OXC administered during gestation is pro-apoptotic, alters the cytoarchitecture of the hippocampus, reduces litter size, and probably influences postnatal weight. We provide evidence of the proapoptotic effect of CBZ when administered early in gestation.

Leaching behavior of pharmaceuticals and their metabolites in the soil environment

Pharmaceuticals constitute a significant group of emerging pollutants (EPs). The use of pharmaceuticals in animal breeding causes them to reach the soil environment in excrement and fertilizers. Depending on their chemical properties, pharmaceuticals can be sorbed to the soil or be washed out with rainfall and eventually be entered into groundwater. This paper evaluates the mobility of tramadol (TRA) and carbamazepine (CBZ), and two transformation products, O-desmethyltramadol (O-DMTRA) and 10,11-dihydro-10-hydroxycarbamazepine (10-OH-CBZ) in soils. Both pharmaceuticals are applied in human and animal treatment, which makes them enter the environment in native and metabolized form in high doses. Experiments were carried out in accordance with the OECD 106 procedure (batch tests) and DIN 19528:2009-01 procedure (percolation column test). The adsorption coefficients (K_d) for TRA, CBZ, O-DMTRA and 10-OH-CBZ were, respectively, 1.41 ± 0.10, 1.87 ± 0.06, 0.90 ± 0.03 and 0.37 ± 0.07 for sandy soil RS04, and 18.09 ± 0.78, 2.56 ± 0.05, 10.89 ± 0.17 and 0.56 ± 0.38  L kg^-1 for loamy soil RS06. The percolation column test was carried out for sandy soil RS04. The results obtained for TRA and O-DMTRA under static conditions indicated a high mobility of these compounds in soil, whereas the column leaching experiment showed that these compounds bind strongly to soil particles. A correlation between static and dynamic tests was observed in the case of CBZ and 10-OH-CBZ. These compounds will probably be characterized by a high or moderate mobility in soil.

Pharmacotherapy for Focal Seizures in Children and Adolescents

Focal-onset seizures are among the most common forms of seizures in children and adolescents and can be caused by a wide diversity of acquired or genetic etiologies. Despite the increasing array of antiseizure drugs available, treatment of focal-onset seizures in this population remains problematic, with as many as one-third of children having seizures refractory to medications. This review discusses contemporary concepts in focal seizure classification and pathophysiology and describes the antiseizure medications most commonly chosen for this age group. As antiseizure drug efficacy is comparable in children and adults, here we focus on pharmacokinetic aspects, drug-drug interactions, and side effect profiles. Finally, we provide some suggestions for choosing the optimal medication for the appropriate patient.

The unmasking of hidden severe hyponatremia after long-term combination therapy in exacerbated bipolar patients: a case series

Hyponatremia is occasionally unmasked in psychiatric patients during hospitalization after routine blood and urinary tests, and correlates in most cases with an inappropriate secretion of antidiuretic hormone, mainly due to iatrogenic factors. Only a few studies have regarded the combination of psychotropic drugs as triggers of chronic, asymptomatic hyponatremia in bipolar patients, who require to be hospitalized because of the exacerbation of their mental illness. We presented three clinical cases of patients affected by a long-term psychiatric disorder and under polypharmacotherapy for several months. After excluding other potential factors, we hypothesized that pharmacological treatment with a mood stabilizer (oxcarbazepine) associated with a benzodiazepine (delorazepam), a second-generation antipsychotic (olanzapine) or an antidepressant (fluvoxamine), triggered severe hyponatremia ([Na+] ≤125 mEq/L), serum hypo-osmolarity, and elevated inappropriate urine osmolarity added to more diluted sodium concentration. When we discontinued the treatment, clinical conditions of our patients improved, despite the previous administration of hypertonic saline jointly with water restriction. Psychiatrists should consider that bipolar patients on long-term polypharmacotherapy may present a higher risk of severe hyponatremia not clinically detectable. Consequently, routine laboratory tests should be periodically repeated as they represent the only available tool to unmask such electrolyte imbalances.

A Tailored Thermosensitive PLGA-PEG-PLGA/Emulsomes Composite for Enhanced Oxcarbazepine Brain Delivery via the Nasal Route

The use of nanocarrier delivery systems for direct nose to brain drug delivery shows promise for achieving increased brain drug levels as compared to simple solution systems. An example of such nanocarriers is emulsomes formed from lipid cores surrounded and stabilised by a corona of phospholipids (PC) and a coating of Tween 80, which combines the properties of both liposomes and emulsions. Oxcarbazepine (OX), an antiepileptic drug, was entrapped in emulsomes and then localized in a poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymer thermogel. The incorporation of OX emulsomes in thermogels retarded drug release and increased its residence time (MRT) in rats. The OX-emulsome and the OX-emulsome-thermogel formulations showed in vitro sustained drug release of 81.1 and 53.5%, respectively, over a period of 24 h. The pharmacokinetic studies in rats showed transport of OX to the systemic circulation after nasal administration with a higher uptake in the brain tissue in case of OX-emulsomes and highest MRT for OX-emulsomal-thermogels as compared to the IN OX-emulsomes, OX-solution and Trileptal® suspension. Histopathological examination of nasal tissues showed a mild vascular congestion and moderate inflammatory changes around congested vessels compared to saline control, but lower toxic effect than that reported in case of the drug solution.

Hypothyroidism induced by phenytoin and gabapentin: A Case Report

RATIONALE

Antiepileptic drugs (AEDs) are one of the causative drugs of drug-induced hypothyroidism. In most cases, AED-induced hypothyroidism is subclinical and indicated only by abnormalities of free thyroxine (T4) and/or thyroid-stimulating hormone (TSH) levels. Severe symptomatic hypothyroidism following AEDs is rarely reported in the literature.

PATIENT CONCERNS

A 75-year-old man experienced neurologic symptoms including memory impairment, ataxic gait, sensory polyneuropathy and myopathy, lethargy, and edema of the face and lower extremities. He had been administered phenytoin and gabapentin for the treatment of symptomatic traumatic epilepsy 8 years before.

DIAGNOSES

The patient had low free T4 (0.21 ng/dL) and high TSH (113.2 μIU/mL), which indicated hypothyroidism. Negative thyroid-related autoantibody tests and the lack of goiter excluded the possibility of Hashimoto disease. Phenytoin and/or gabapentin were strongly suspected as causing his hypothyroidism.

INTERVENTION

The patient was treated with replacement therapy (levothyroxine 25 μg/day).

OUTCOMES

His symptoms markedly and promptly improved alongside continued antiepileptic therapy.

LESSONS

In this case, the patient's hypothyroidism was assumed to result from different mechanisms of the 2 AEDs leading to thyroid hormone reduction. AEDs can not only cause asymptomatic thyroid hormone abnormalities but also clinically observable hypothyroidism. Therefore, clinicians should be aware of the association between anticonvulsants and symptomatic hypothyroidism.

Dibenzazepine Agents in Epilepsy: How Does Eslicarbazepine Acetate Differ?

Carbamazepine (CBZ), oxcarbazepine (OXC), and eslicarbazepine acetate (ESL) belong to the dibenzazepine family of antiepileptic drugs and are all thought to primarily act as sodium channel blockers (SCBs). However, ESL is structurally distinct from CBZ and OXC, resulting in differences in metabolism, pharmacokinetics, and pharmacodynamics. Despite a lack of direct comparative data, evidence for potential differences in effectiveness and tolerability within the dibenzazepine family has emerged from studies in which patients being treated with one dibenzazepine agent have received adjunctive treatment with another (having achieved insufficient seizure control with the first) or have transitioned from one dibenzazepine agent to another because of lack of effectiveness or poor tolerability. Most of these studies have been conducted in the real-world clinical practice setting. ESL has been shown to be effective as adjunctive therapy in patients who have previously achieved inadequate seizure control with CBZ, indicating that the use of different dibenzazepine agents in combination can provide additive effectiveness benefits, which may reflect underlying differences in their mechanisms of action. Similarly, ESL monotherapy can be effective in patients who have switched from another dibenzazepine, such as CBZ or OXC, because of inadequate efficacy. There is also considerable evidence to demonstrate that patients transitioning from OXC or CBZ to ESL as a result of adverse events experience improvements in tolerability, which may also be associated with improvements in quality of life, alertness, and/or lipid profiles. Current evidence therefore demonstrates that ESL differs from other dibenzazepine agents in terms of effectiveness and tolerability.

Funding: Eisai Ltd.

Association between HLA-B*15:02 and oxcarbazepine-induced cutaneous adverse reaction: a meta-analysis

Aim: HLA-B*15:02 has been demonstrated as a key risk factor for carbamazepine-induced severe cutaneous adverse reaction (sCAR), especially in Asian population. Oxcarbazepine (OXC) is a drug that has a similar structure of carbamazepine. However, the relationship between HLA-B*15:02 and induced cutaneous adverse reaction (cADR) remains unknown. This study aims to analyze this association in the published literature. Method: After filtering studies, eight studies were finally included for meta-analysis, including 32 sCAR cases, 112 mild cutaneous adverse reaction (mcADR) cases, 281 OXC tolerant control and 946 population control cases. Result: In the tolerant control group, an association was found between HLA-B*15:02 genotype and OXC-induced sCAR (odds ratio [OR]: 18.13; 95% CI: 6.77–48.56), but not in mcADR (OR: 1.43; 95% CI: 0.56–3.64). In population control group, an association was found between HLA-B*15:02 genotype and OXC-induced sCAR, (OR: 8.22; 95% CI: 3.03–22.34), but not in mcADR (OR: 2.06; 95% CI: 0.91–4.67). Discussion: Our study demonstrates that the genetic risk factor HLA-B*15:02 may be a factor in OXC-induced sCAR.

HLA-A*31:01 and Oxcarbazepine-Induced DRESS in a Patient With Seizures and Complete DCX Deletion

Oxcarbazepine is an antiepileptic drug (AED) commonly used as a first-line treatment option for focal epilepsy. Several AEDs, including carbamazepine, oxcarbazepine, and phenytoin are associated with various delayed-hypersensitivity reactions such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, or toxic epidermal necrolysis. The Food and Drug Administration-approved label for oxcarbazepine currently presents information regarding a pharmacogenomic association with the HLA antigen allele HLA-B*15:02 and hypersensitivity reactions in certain ancestry groups with a high incidence of this allele. However, unlike carbamazepine, screening for the presence of this allele is not routinely recommended before administration of oxcarbazepine. In practice, even with carbamazepine, HLA antigen testing is not always performed before initiating treatment because of lack of physician awareness of the recommendations and because of the desire to initiate treatment without delay. We present the clinical course of a pediatric patient with focal epilepsy refractory to several AEDs who developed drug reaction with eosinophilia and systemic symptoms after oxcarbazepine administration. The pharmacogenomic testing for various HLA antigen alleles was performed post hoc, and results were evaluated for structural similarities between AEDs and their molecular associations with HLA antigen proteins. In addition, we review the population-wide prevalence of various hypersensitivity reactions to AEDs and associated HLA antigen alleles. Finally, we discuss the potential utility of preemptive pharmacogenomic screening of patients before pharmacological treatment of epilepsy to assess the risk of developing hypersensitivity reactions.

The neurotoxic effects of prenatal gabapentin and oxcarbazepine exposure on newborn rats

AIM

Teratogenicity is a problematic issue for pregnant women because of X-ray radiation, drugs, and genetic and unknown variables. First-generation antiepileptic drugs (AED) like valproic acid are well-known teratogens for developing fetuses. However, their usage is necessary in order to prevent maternal seizures. The underlying mechanism of birth defects associated with AED exposure remains unclear and information about the neurotoxic effects of prenatal exposure to AED is still limited. Oxcarbazepine (OXC) and gabapentin (GBP) are second-generation AED. It still remains unclear how much these drugs are safe during pregnancy. This study aimed to investigate whether any neurotoxic effect of OXC and GBP in utero exposure on the developing brain.

METHODS

Eighteen pregnant Wistar albino rats were divided into six groups. The first group was exposed to OXC at 100 mg/kg/day, the second to GBP at 50 mg/kg/day, and third to saline (0.9% NaCl) at 1.5 ml/day between the first and the fifth days of gestation. The same procedure was applied at the same dosages between the 6th and the 15th days of gestation for the 2nd three groups. Five female offspring (total n = 30, 45 days old) were taken from each group and stereological methods were applied in order to analyze the total and dopaminergic neuron number of the substantia nigra pars compacta (SNc).

CONCLUSION

The result is that the OXC and GBP exposure at different gestational periods may not give rise to congenital malformation and it appears that the GBP exposure during the organogenesis period proliferatively affects the total number of neurons.

Effects of ABCB1, ABCC2, UGT2B7 and HNF4α genetic polymorphisms on oxcarbazepine concentrations and therapeutic efficacy in patients with epilepsy

PURPOSE

The aim of the study is to investigate the effects of ABCB1, ABCC2, UGT2B7 and HNF4α genetic polymorphisms on plasma oxcarbazepine (OXC) concentrations and therapeutic efficacy in Han Chinese patients with epilepsy.

METHODS

We recruited 116 Han Chinese patients with epilepsy who were receiving OXC monotherapy. Blood samples were taken and OXC levels were measured. The polymorphisms of ABCB1 rs1045642, ABCC2 rs2273697, UGT2B7 rs7439366, and HNF4α rs2071197 were determined. The therapeutic efficacy of OXC at the 1-year time-point was assessed. Data analysis was performed using IBM SPSS Statistics 22.0.

RESULTS

The genetic polymorphism of ABCB1 rs1045642 was found to be associated with normalized OXC concentration and therapeutic efficacy in patients with epilepsy (P<0.05). As for UGT2B7 rs7439366, the allele polymorphism exhibited a correlation with treatment outcome, but not OXC concentration. The polymorphisms of ABCC2 rs2273697 and HNF4α rs2071197 was not associated with OXC concentrations and therapeutic efficacy.

CONCLUSION

These results suggested that ABCB1 rs1045642 and UGT2B7 rs7439366 may affect OXC pharmacokinetics and therapeutic efficacy in Han Chinese patients with epilepsy. However, further studies in larger populations and other ethnic groups are required.

Oxcarbazepine in Mood Disorders

Patients with bipolar illness or schizoaffective disorder–manic type can present with a variety of symptoms and have mixed responses to treatment. This is especially true for patients who have rapid cycling or mixed bipolar illness. The following cases describe the use of oxcarbazepine in patients with either bipolar illness or schizoaffective disorder. This agent, an analogue of carbamazepine, has fewer drug–drug interactions and side effects and thus may prove to be a better tolerated agent in the treatment of these very serious illnesses. A discussion of the properties of oxcarbazepine is also included.

The genotoxic effect of oxcarbazepine on mice blood lymphocytes

This study was conducted to assess the amount of DNA damage caused by Oxcarbazepine (OXC) through single cell gel electrophoresis (SCGE) technique/comet assay. OXC derived from dibenzazepine series is an effective second generation antiepileptic drug (AED) for both children and adults. Side effects like genotoxic effects of AEDs are of prime importance resulting from toxic metabolites, free radicals and reactive oxygen species (ROS). Forty Eight adult male Bagg's albino mice (BALB/c) were randomly classified into eight groups, each comprising of six animals. Two of these groups were control and six were tested groups. Control groups were injected with 1% tween 80 while tested groups were injected with 10, 20, and 40 mg/kg-day OXC for seven days (acute therapy) and 28 days (subchronic therapy) in peritoneal cavity. Blood samples were collected by cardiac puncture and subjected to comet assay for the analysis of DNA damage. Per sample 100 cells were scored and classified according to comet tail length. The results showed that OXC in acute and long term therapies had significantly higher (p < 0.05) genotoxicity in treated groups as compared to control groups. Our study suggests that OXC may cause significant DNA damage in both acute as well as in subchronic therapies.

Activity Clamp Provides Insights into Paradoxical Effects of the Anti-Seizure Drug Carbamazepine

A major challenge in experimental epilepsy research is to reconcile the effects of anti-epileptic drugs (AEDs) on individual neurons with their network-level actions. Highlighting this difficulty, it is unclear why carbamazepine (CBZ), a frontline AED with a known molecular mechanism, has been reported to increase epileptiform activity in several clinical and experimental studies. We confirmed in an in vitro mouse model (in both sexes) that the frequency of interictal bursts increased after CBZ perfusion. To address the underlying mechanisms, we developed a method, activity clamp, to distinguish the response of individual neurons from network-level actions of CBZ. We first recorded barrages of synaptic conductances from neurons during epileptiform activity and then replayed them in pharmacologically isolated neurons under control conditions and in the presence of CBZ. CBZ consistently decreased the reliability of the second action potential in each burst of activity. Conventional current-clamp recordings using excitatory ramp or square-step current injections failed to reveal this effect. Network modeling showed that a CBZ-induced decrease of neuron recruitment during epileptic bursts can lead to an increase in burst frequency at the network level by reducing the refractoriness of excitatory transmission. By combining activity clamp with computer simulations, the present study provides a potential explanation for the paradoxical effects of CBZ on epileptiform activity.

SIGNIFICANCE STATEMENT The effects of anti-epileptic drugs on individual neurons are difficult to separate from their network-level actions. Although carbamazepine (CBZ) has a known anti-epileptic mechanism, paradoxically, it has also been reported to increase epileptiform activity in clinical and experimental studies. To investigate this paradox during realistic neuronal epileptiform activity, we developed a method, activity clamp, to distinguish the effects of CBZ on individual neurons from network-level actions. We demonstrate that CBZ consistently decreases the reliability of the second action potential in each burst of epileptiform activity. Network modeling shows that this effect on individual neuronal responses could explain the paradoxical effect of CBZ at the network level.

Effects of UGT1A9 genetic polymorphisms on monohydroxylated derivative of oxcarbazepine concentrations and oxcarbazepine monotherapeutic efficacy in Chinese patients with epilepsy

AIM

The human UDP-glucuronosyltransferase which is genetically polymorphic catalyzes glucuronidations of various drugs. The interactions among UGT1A4, UGT1A6, UGT1A9, and UGT2B15 genetic polymorphisms, monohydroxylated derivative (MHD) of oxcarbazepine (OXC) plasma concentrations, and OXC monotherapeutic efficacy were explored in 124 Chinese patients with epilepsy receiving OXC monotherapy.

METHOD

MHD is the major active metabolite of OXC, and its plasma concentration was measured using high-performance liquid chromatography when patients reached their maintenance dose of OXC. Genomic DNA was extracted from whole blood and SNP genotyping performed using PCR followed by dideoxy chain termination sequencing. We followed the patients for at least 1 year to evaluate the OXC monotherapy efficacy. Patients were divided into two groups according to their therapeutic outcome: group 1, seizure free; group 2, not seizure free. The data were analyzed using T test, one-way analysis of variance (ANOVA), Kruskal-Wallis test, chi-square test, Fisher's exact test, correlation analysis, and multivariate regression analysis.

RESULT

T test analysis showed that MHD plasma concentrations were significantly different between the two groups (p = 0.002). One-way ANOVA followed by Bonferroni post hoc testing of four candidate SNPs revealed that carriers of the UGT1A9 variant allele I399 C > T (TT 13.28 ± 7.44 mg/L, TC 16.41 ± 6.53 mg/L) had significantly lower MHD plasma concentrations and poorer seizure control than noncarriers (CC 22.24 ± 8.49 mg/L, p < 0.05).

CONCLUSION

In our study, we have demonstrated the effects of UGT1A9 genetic polymorphisms on MHD plasma concentrations and OXC therapeutic efficacy. Through MHD monitoring, we can predict OXC therapeutic efficacy, which may be useful for the personalization of OXC therapy in epileptic patients.

HLA-B*40:02 and DRB1*04:03 are risk factors for oxcarbazepine-induced maculopapular eruption

OBJECTIVE

Oxcarbazepine (OXC) is a widely used antiepileptic drug for the treatment of partial seizures that was developed through structural variation of carbamazepine. Although OXC has a lower risk of cutaneous adverse drug reactions (cADRs) than carbamazepine, cADRs ranging from maculopapular eruption (MPE) to the more severe Stevens-Johnson syndrome and toxic epidermal necrolysis still limit the use of OXC in some patients. A few human leukocyte antigen (HLA)-related genetic risk factors for carbamazepine-induced cADRs have been identified. However, the HLA-related genetic risk factors associated with OXC-induced cADRs are unknown.

METHODS

A total of 40 patients who experienced OXC-induced MPE and 70 patients who were tolerant to OXC treatment were included in the study. Genomic DNA was extracted from the peripheral blood of these patients, and high-resolution HLA genotyping was performed.

RESULTS

The HLA-B*40:02 and HLA-DRB1*04:03 alleles were significantly associated with OXC-induced MPE compared with the OXC-tolerant group (odds ratio [OR] 4.33, p = 0.018 and OR 14.64, p = 0.003, respectively) and the general Korean population (OR 4.04, p = 0.001 and OR 3.11, p = 0.019, respectively). The HLA-B*15:01 genetic frequency was significantly lower in the OXC-MPE group compared to the OXC-tolerant group (OR 0.18, p = 0.016) and the Korean population (OR 0.22, p = 0.030). The allele frequencies of well-known HLA-related risk factors for carbamazepine-induced cADRs (HLA-B*15:02, A*31:01 and B*15:11) were not different among the three groups.

SIGNIFICANCE

This study is the first to demonstrate an association of HLA-B*40:02 and HLA-DRB1*04:03 with OXC hypersensitivity using a large cohort of patients with OXC-induced MPE. These findings should be confirmed in future studies in different ethnic groups.

Effective Treatment of Paroxysmal Nonkinesigenic Dyskinesia With Oxcarbazepine

Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare chronic disorder characterized by intermittent, non-movement-related involuntary movements. The response to currently available therapies is inconsistent and temporary. We describe here a patient with infantile-onset PNKD who failed a number of pharmaceutical agents used alone or in combination. Treatment with oxcarbazepine resulted in a substantial reduction in the frequency and severity of episodes. The patient has been followed for 4 years now, and the outcome of treatment is consistently favorable. Oxcarbazepine has been effective in managing the kinesigenic form of this disorder; however, its use has never been reported in PNKD to our knowledge. Oxcarbazepine is safer and better tolerated than most of the drugs currently used for treating PNKD, but blinded clinical trials are needed to verify its efficacy in the management of this debilitating, often difficult-to-treat disease.

Comparative Long-Term Effectiveness of a Monotherapy with Five Antiepileptic Drugs for Focal Epilepsy in Adult Patients: A Prospective Cohort Study

Objective

To evaluate and compare long-term effectiveness of five antiepileptic drugs (AEDs) for monotherapy of adult patients with focal epilepsy in routine clinical practice.

Methods

Adult patients with focal epilepsy, who were prescribed with carbamazepine (CBZ), valproate (VPA), lamotrigine (LTG), topiramate (TPM), or oxcarbazepine (OXC) as monotherapy, during the period from January 2004 to June 2012 registered in Wenzhou Epilepsy Follow Up Registry Database (WEFURD), were included in the study. Prospective long-term follow-up was conducted until June 2013. The endpoints were time to treatment failure, time to seizure remission, and time to first seizure.

Results

This study included 654 patients: CBZ (n=125), VPA (n=151), LTG (n=135), TPM (n=76), and OXC (n=167). The retention rates of CBZ, VPA, LTG, TPM, and OXC at the third year were 36.1%, 32.4%, 57.6%, 37.9%, and 41.8%, respectively. For time to treatment failure, LTG was significantly better than CBZ and VPA (LTG vs. CBZ, hazard ratio, [HR] 0.80 [95% confidence interval: 0.67-0.96], LTG vs. VPA, 0.53 [0.37-0.74]); TPM was worse than LTG (TPM vs. LTG, 1.77 [1.15-2.74]), and OXC was better than VPA (0.86 [0.78-0.96]). After initial target doses, the seizure remission rates of CBZ, VPA, LTG, TPM, and OXC were 63.0%, 77.0%, 83.6%, 67.9%, and 75.3%, respectively. LTG was significantly better than CBZ (1.44 [1.15-1.82]) and OXC (LTG vs. OXC, 0.76 [0.63-0.93]); OXC was less effective than LTG in preventing the first seizure (1.20 [1.02-1.40]).

Conclusion

LTG was the best, OXC was better than VPA only, while VPA was the worst. The others were equivalent for comparisons between five AEDs regarding the long-term treatment outcomes of monotherapy for adult patients with focal epilepsy in a clinical practice. For selecting AEDs for these patients among the first-line drugs, LTG is an appropriate first choice; others are reservation in the first-line but VPA is not.

Efficacy of low to moderate doses of oxcarbazepine in adult patients with newly diagnosed partial epilepsy

PURPOSE

The objective of this study was to explore the efficacy of low dose of oxcarbazepine (OXC) in adult patients with newly diagnosed partial epilepsy in an actual clinical setting. The associated factors influencing the poor control of seizures were also evaluated.

METHODS

The epilepsy database (2010-2014) from the Epilepsy Clinic of West China Hospital was retrospectively reviewed.

RESULTS

A total of 102 adult patients with newly diagnosed, previously untreated partial epilepsy initially treated with OXC were included, and divided into good response group (64) and poor response group (38) according to whether they were seizure-free for at least 12 months. There were 27 (26.5%) patients becoming seizure-free with OXC 600 mg/day monotherapy. The remaining 75 patients had doses of either increasing OXC to 900 mg/day (n = 59) or the addition of another antiepileptic drug (AED) (n = 16), with another 20 (19.6%) and six (5.9%) patients becoming seizure-free, respectively (P = 0.788). In addition, two (2.0%) and nine (8.8%) patients became seizure-free with OXC > 900 mg/day monotherapy and OXC ≥ 900 mg/day combination therapy, respectively. Multivariate binary logistic regression analysis revealed that the time from onset of epilepsy to treatment initiation is significantly associated with seizure control (P = 0.02).

CONCLUSION

Our results indicated that OXC at low to moderate doses is effective for the treatment of Chinese adult patients with newly diagnosed, previously untreated partial epilepsy, and a longer time interval from the onset of epilepsy to the start of treatment significantly predicts poor seizure control.

Long-term safety and efficacy of eslicarbazepine acetate in patients with focal seizures: results of the 1-year ESLIBASE retrospective study

BACKGROUND

Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED) licensed as adjunctive therapy in adults with partial-onset or focal seizures.

OBJECTIVE

To evaluate in a clinical practice setting the long-term efficacy and safety of ESL in patients with focal seizures.

METHODS

ESLIBASE was a retrospective study that included all patients with focal seizures who started ESL between January 2010 and July 2012 at 12 hospitals. ESL was prescribed individually according to real-life practice. Efficacy and safety were evaluated over 1 year. Switching from carbamazepine (CBZ) and oxcarbazepine (OXC) was assessed.

RESULTS

Three hundred and twenty-seven patients were included; 78% of patients were taking ≥2 other AEDs at baseline. Most (87%) began ESL because of poor seizure control and 13% because of adverse events (AEs) with CBZ or OXC. After 1 year, 237 patients (72.4%) remained on ESL. At 3, 6 and 12 months, the responder rate was 46.3%, 57.9%, and 52.5%, and 21.0%, 28.0%, and 25.3% of patients were seizure free. The responder rate significantly increased when ESL was combined with a non-sodium channel-targeting drug (non-SC drug) (66.7%) versus an SC drug (47.7%; p<0.001). At 12 months, 40.7% of patients had ≥1 AE; AEs led to treatment discontinuation in 16.2%. Dizziness, nausea, and somnolence were the most common AEs. The tolerability profile improved in >50% of the patients who switched from CBZ or OXC to ESL because of AEs.

CONCLUSIONS

ESL was well tolerated and effective in a real-world setting over 1 year. Side-effect profile improved when OXC and CBZ recipients were switched to ESL.

Implications of pharmacogenetics for the therapeutic use of antiepileptic drugs

INTRODUCTION

Epilepsy is a chronic neurological disease manifesting as recurrent seizures. Despite the availability of numerous antiepileptic drugs (AEDs), one-third of the patients are not responsive to treatment. Such inter-individual variability in the response to AEDs may be partly explained by genetic differences. This review summarizes the pharmacogenetics (PGx) of AEDs. In addition, a model-based approach is presented that enables the integration of PGx data with other relevant sources of variability, such as demographic characteristics and co-medications.

AREAS COVERED

A comprehensive overview is provided of the data available in the literature on the evidence for correlations between genetic mutations and pharmacokinetic (PK) and/or pharmacodynamics (PD) of AEDs. This information is then used in an integrated manner in the second part, where PGx differences are parameterized as covariates in PK and PKPD models.

EXPERT OPINION

Polymorphisms are profuse in the PK and PD of AEDs. However, understanding of their clinical implication remains limited due to the lack of methodologies that discriminate the contribution of other sources of variability in CNS exposure to drugs. A model-based approach, in which other intrinsic (e.g., demographic covariates) and extrinsic (e.g., drug-drug interactions) factors are evaluated concurrently is needed to ensure optimization and individualization of treatment in epileptic patients.

A structurally diverse heterocyclic library by decoration of oxcarbazepine scaffold

A library of new heterocyclic systems was synthesized starting from oxcarbazepine (OXC, Trileptal^®, 10-oxo-10,11-dihydro-5H-dibenzo[b,f]azepine-5-carboxamide). The key for these transformations is the α-enolizable ketone present on the [d]-side of our starting material OXC, thus, an in depth investigation of the literature to find heteroannulation reactions for substrates carrying an α-enolizable ketone gave us a boost to discover an excellent derivatization strategy and [3+2], [4+2] and [4+1] approaches were successfully developed. Almost always a pre-functionalization was needed, but also the direct one-pot heterocycle construction was also explored.