Oxcarbazepine: a review of its use in children with epilepsy

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.

Synthesis of rod-like CeO2 nanoparticles and their application to catalyze the luminal-O2 chemiluminescence reaction used in the determination of oxcarbazepine and ascorbic acid

Rod-like CeO₂ nanoparticles (NPs) were produced by the quick precipitation approach and employed as a catalyzer to increase the chemiluminescence (CL) intensity of the luminol-O₂ reaction. The transmission electron microscopy (TEM) images of the CeO₂ NPs showed that rod-like particles with the length and diameter about 15 nm and 5 nm, respectively, were produced. Furthermore, pharmaceuticals including oxcarbazepine (OXP) and ascorbic acid (AA) showed an inhibitory effect against the CL intensity such that the more concentration of the pharmaceuticals, the less was the CL intensity. Therefore, the new CeO₂ NPs-luminol-O₂ CL reaction was developed to determine OXP and AA in the pharmaceutical formulations. It is the first CL method established for the quantification of OXP. The linear dynamic range of this method for OXP was from 6.0 × 10^-7 to 6.0 × 10^-5 mol L^-1 and for AA from 1.0 × 10^-6 to 1.0 × 10^-4 mol L^-1.

Precision Medicine into Clinical Practice: A Web-Based Tool Enables Real-Time Pharmacogenetic Assessment of Tailored Treatments in Psychiatric Disorders

The management of neuropsychiatric disorders involves different pharmacological treatments. In order to perform efficacious drug treatments, the metabolism of CYP genes can help to foresee potential drug–drug interactions. The NeuroPGx software is an open-source web-based tool for genotype/diplotype/phenotype interpretation for neuropharmacogenomic purposes. The software provides information about: (i) the genotypes of evaluated SNPs (single nucleotide polymorphisms); (ii) the main diplotypes in CYP genes and corresponding metabolization phenotypes; (iii) the list of neuropsychiatric drugs with recommended dosage adjustment (according to CPIC and DPWG guidelines); (iv) the list of possible (rare) diplotypes and corresponding metabolization phenotypes. The combined application of NeuroPGx software to the OpenArray technology results in an easy, quick, and highly automated device ready to be used in routine clinical practice.

Post-treatment with oxcarbazepine confers potent neuroprotection against transient global cerebral ischemic injury by activating Nrf2 defense pathway

Oxcarbazepine (OXC), a voltage-gated sodium channel blocker, is an antiepileptic medication and used for the bipolar disorders treatment. Some voltage-gated sodium channel blockers have been demonstrated to display strong neuroprotective properties in models of cerebral ischemia. However, neuroprotective effects and mechanisms of OXC have not yet been reported. Here, we investigated the protective effect of OXC and its mechanisms in the cornu ammonis 1 subfield (CA1) of gerbils subjected to 5 min of transient global cerebral ischemia (tGCI). tGCI led to death of most pyramidal neurons in CA1 at 5 days after ischemia. OXC (100 and 200 mg/kg) was intraperitoneally administered once at 30 min after tGCI. Treatment with 200 mg/kg, not 100 mg/kg OXC, significantly protected CA1 pyramidal neurons from tGCI-induced injury. OXC treatment significantly decreased superoxide anion production, 4-hydroxy-2-nonenal and 8-hydroxyguanine levels in ischemic CA1 pyramidal neurons. In addition, the treatment restored levels of superoxide dismutases, catalase, and glutathione peroxidase. Furthermore, the treatment distinctly inhibited tGCI-induced microglia activation and significantly reduced levels of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α). In particular, OXC treatment significantly enhanced expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream protein heme oxygenase-1 in ischemic CA1. The neuroprotective effects of OXC were abolished by brusatol (an inhibitor of Nrf2). Taken together, these results indicate that post-treatment of OXC can display neuroprotection against brain injuries following ischemic insults. This neuroprotection may be displayed by attenuation of oxidative stress and neuroinflammation, which can be mediated by activation of Nrf2 pathway.

Oxcarbazepine versus phenytoin monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the Cochrane Review previously published in 2013. This review is one in a series of Cochrane Reviews investigating pair-wise monotherapy comparisons.Epilepsy is a common neurological condition in which abnormal electrical discharges from the brain cause recurrent unprovoked seizures. It is believed that with effective drug treatment, up to 70% of individuals with active epilepsy have the potential to become seizure-free and go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, phenytoin is a commonly used antiepileptic drug. It is important to know how newer drugs, such as oxcarbazepine, compare with commonly used standard treatments.

OBJECTIVES

To review the time to treatment failure, remission and first seizure with oxcarbazepine compared to phenytoin, when used as monotherapy in people with focal onset seizures or generalised tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

We searched the following databases on 20 August 2018: the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to 20 August 2018), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

We included randomised controlled trials comparing monotherapy with either oxcarbazepine or phenytoin in children or adults with focal onset seizures or generalised onset tonic-clonic seizures.

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review. Our primary outcome was time to treatment failure and our secondary outcomes were time to first seizure post-randomisation, time to six-month and 12-month remission, and incidence of adverse events. We used Cox proportional hazards regression models to obtain trial-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs), using the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

Individual participant data were available for 480 out of a total of 517 participants (93%), from two out of three included trials. For remission outcomes, a HR of less than one indicated an advantage for phenytoin; and for first seizure and treatment failure outcomes, a HR of less than one indicated an advantage for oxcarbazepine.The results for time to treatment failure for any reason related to treatment showed a potential advantage of oxcarbazepine over phenytoin, but this was not statistically significant (pooled HR adjusted for epilepsy type: 0.78 95% CI 0.53 to 1.14, 476 participants, two trials, moderate-quality evidence). Our analysis showed that treatment failure due to adverse events occurred later on with oxcarbazepine than phenytoin (pooled HR for all participants: 0.22 (95% CI 0.10 to 0.51, 480 participants, two trials, high-quality evidence). Our analysis of time to treatment failure due to lack of efficacy showed no clear difference between the drugs (pooled HR for all participants: 1.17 (95% CI 0.31 to 4.35), 480 participants, two trials, moderate-quality evidence).We found no clear or statistically significant differences between drugs for any of the secondary outcomes of the review: time to first seizure post-randomisation (pooled HR adjusted for epilepsy type: 0.97 95% CI 0.75 to 1.26, 468 participants, two trials, moderate-quality evidence); time to 12-month remission (pooled HR adjusted for epilepsy type 1.04 95% CI 0.77 to 1.41, 468 participants, two trials, moderate-quality evidence) and time to six-month remission (pooled HR adjusted for epilepsy type: 1.06 95% CI 0.82 to 1.36, 468 participants, two trials, moderate-quality evidence).The most common adverse events reported in more than 10% of participants on either drug were somnolence (28% of total participants, with similar rates for both drugs), headache (15% of total participants, with similar rates for both drugs), dizziness (14.5% of total participants, reported by slightly more participants on phenytoin (18%) than oxcarbazepine (11%)) and gum hyperplasia (reported by substantially more participants on phenytoin (18%) than oxcarbazepine (2%)).The results of this review are applicable mainly to individuals with focal onset seizures; 70% of included individuals experienced seizures of this type at baseline. The two studies included in IPD meta-analysis were generally of good methodological quality but the design of the studies may have biased the results for the secondary outcomes (time to first seizure post-randomisation, time to six-month and 12-month remission) as seizure recurrence data were not collected following treatment failure or withdrawal from the study. In addition, misclassification of epilepsy type may have impacted on results, particularly for individuals with generalised onset seizures.

AUTHORS' CONCLUSIONS

High-quality evidence provided by this review indicates that treatment failure due to adverse events occurs significantly later with oxcarbazepine than phenytoin. For individuals with focal onset seizures, moderate-quality evidence suggests that oxcarbazepine may be superior to phenytoin in terms of treatment failure for any reason, seizure recurrence and seizure remission. Therefore, oxcarbazepine may be a preferable alternative treatment than phenytoin, particularly for individuals with focal onset seizures. The evidence in this review which relates to individuals with generalised onset seizures is of low quality and does not inform current treatment policy.We recommend that future trials should be designed to the highest quality possible with regards to choice of population, classification of seizure type, duration of follow-up (including continued follow-up after failure or withdrawal of randomised treatment), choice of outcomes and analysis, and presentation of results.

Oxcarbazepine oral suspension in young pediatric patients with partial seizures and/or generalized tonic-clonic seizures in routine clinical practice in China: a prospective observational study

BACKGROUND

This study aimed to assess efficacy and safety of oxcarbazepine (OXC) oral suspension in pediatric patients aged 2-5 years with partial seizures (PS) and/or generalized tonic-clonic seizures (GTCS) in real-world clinical practice in China.

METHODS

This 26-week, prospective, single-arm, multicenter, observational study recruited pediatric patients aged 2-5 years with PS or GTCS suitable for OXC oral suspension treatment based on physicians' judgments from 11 medical centers in China. Enrolled subjects started OXC oral suspension treatment as monotherapy or in combination with other antiepileptic drugs. Primary efficacy outcome was the percentage of pediatric subjects achieving ≥ 50% seizure frequency reduction at the end of the 26-week treatment. Secondary efficacy-related parameters and safety parameters such as adverse events (AEs) and serious AEs (SAEs) were also monitored during the 26-week treatment period.

RESULTS

Six hundred and six pediatric patients were enrolled and 531 (87.6%) completed the study. After 26 weeks of treatment, 93.3% subjects achieved ≥ 50% seizure frequency reduction, and 81.8% achieved 100% seizure frequency reduction compared to baseline. Among different seizure types, OXC was effective in all subjects with simple PS and in > 90% of subject with other type of seizure present in the study. AEs were observed in 49 (8.1%) subjects. Only three subjects experienced SAE. Rash (n = 18, 2.97%) was the most common AE. Only 17 subjects discontinued due to AEs.

CONCLUSION

This study, reporting the real-world data, further confirms the efficacy and good safety profile of OXC oral suspension in Chinese pediatric patients aged 2-5 years with PS and/or GTCS.

Oxcarbazepine oral suspension in pediatric patients with partial seizures and/or generalized tonic-clonic seizures: a multi-center, single arm, observational study in China

BACKGROUND

To assess efficacy and safety of oxcarbazepine (OXC) oral suspension in pediatric patients aged 2-16 years with partial seizures (PS) and/or generalized tonic-clonic seizures (GTCS) in real-world clinical practice in China.

METHODS

This 26-week, single arm, multicenter and observational study recruited patients aged 2-16 years with PS or GTCS suitable for OXC oral suspension treatment. Enrolled patients received OXC oral suspension treatment for 26 weeks. Primary endpoints included mean seizure frequency at the end of the treatment and mean seizure frequency reduction at the end of the treatment vs. baseline. Secondary efficacy-related endpoints and safety parameters were also assessed.

RESULTS

Nine hundred and eighty-seven pediatric patients were enrolled and 912 (92.4%) completed the study. The mean seizure frequencies at baseline and the end of week 26 were 13.40±64.92 and 1.62±19.47 times/ month, respectively. The mean seizure frequency reduction was 10.03±63.67 times/month and the mean seizure frequency reduction percentage was 90.02%±5127.0% (P<0.0001). After 26 weeks of treatment, 82.36%, 7.24% and 3.86% of the patients became controlled, significantly improved and improved, respectively. Adverse events (AEs) were reported in 74 (7.65%) patients. Rash was the most common AE. The efficacy of OXC was not affected by seizure types, age or gender.

CONCLUSIONS

This study confirms the efficacy and good safety profile of OXC oral suspension in Chinese pediatric patients aged 2-16 years with PS and/or GTCS.

Weight gain in children on oxcarbazepine monotherapy

BACKGROUND

Studies of the effect of oxcarbazepine (OXC) on body growth of children with epilepsy are rare and their results are controversial. To the contrary, many studies have shown significant weight gain following valproate (VPA) treatment.

PURPOSE

To prospectively evaluate the effect of OXC monotherapy on growth patterns of children with epilepsy and compare it with the effect of VPA monotherapy.

METHOD

Fifty-nine otherwise healthy children, aged 3.7-15.9 years, with primary generalized, partial or partial with secondary generalization seizure disorder, were included in the study. Twenty six children were placed on OXC and thirty three on VPA monotherapy. Body weight (BW), height and body mass index (BMI) as well as their standard deviation scores (SDS), were evaluated prior to as well as 8 months post initiation of OXC or VPA therapy.

RESULTS

Eight months post OXC-treatment, BW, SDS-BW, BMI and SDS-BMI increased significantly. The increase was similar to that observed in the VPA group. An additional 15.4% of children in the OXC group and 21.2% in the VPA group became overweight or obese. The effect of both OXC and VPA therapy on linear growth did not reach statistical significance.

CONCLUSION

Similarly to VPA, OXC monotherapy resulted in a significant weight gain in children with epilepsy. Careful monitoring for excess weight gain along with counseling on adapting a healthy lifestyle should be offered to children on OXC therapy.

A comparison of the efficacy and tolerability of oxcarbazepine oral suspension between infants and children with epilepsy: a retrospective chart review at a single medical center in Taiwan

BACKGROUND

Few clinical studies have assessed the efficacy and safety of oxcarbazepine (OXC) oral suspension in Asian pediatric patients and particularly in infants. The aim of this study was to investigate and compare the efficacy, tolerability, and side effects of OXC oral suspension in Taiwanese infants and children with various types of epilepsy.

METHODS

A retrospective review of the efficacy, tolerability, and side effects of OXC oral suspension in a tertiary medical center in Taiwan was conducted and included children (1-9 years old) and infants (<1 year old) diagnosed with epilepsy, which was classified into idiopathic partial, symptomatic partial, or multifocal subtypes. The OXC oral suspension (Trileptal(®); Novartis) was given in a gradual dose titration, from an initial 7.5 mg/kg/day to 30 mg/kg/day within 1 month in all cases.

RESULTS

A total of 20 infants and 38 children were identified. There were no statistically significant differences between the children and infants in efficacy (75 vs. 82 %, p = 0.734) and adverse effects (30 vs. 21 %, p = 0.525) after OXC oral suspension treatment. The efficacy was significantly correlated with the epilepsy subtype (p < 0.01) and the number of combined antiepileptic drugs (AEDs) before OXC treatment (p < 0.01) in both groups. The patients with idiopathic and symptomatic partial epilepsy responded better to OXC oral suspension than those with multifocal epilepsy.

CONCLUSIONS

OXC oral suspension is effective and well tolerated in both infants and children with partial epilepsy in Taiwan. Treatment efficacy was related to epilepsy subtype and number of combined AEDs before OXC treatment. Monotherapy had an excellent therapeutic response in partial epilepsy but not in multifocal epilepsy.

Antiepileptic drugs and breastfeeding

INTRODUCTION

This review provides a synopsis for clinicians on the use of antiepileptic drugs (AEDs) in the breastfeeding mother.

METHODS

For each AED, we collected all retrievable data from Hale's "Medications and Mother Milk" (2012), from the LactMed database (2013) of the National Library of Medicine, and from a MedLine Search of relevant studies in the past 10 years.

RESULTS

Older AEDs, such as carbamazepine, valproic acid, phenytoin, phenobarbital, primidone are considered to have a good level of safety during lactation, due to the long term clinical experience and the consequent amount of available data from the scientific literature. On the contrary, fewer data are available on the use of new AEDs. Therefore, gabapentin, lamotrigine, oxcarbazepine, vigabatrin, tiagabine, pregabalin, leviracetam and topiramate are compatible with breastfeeding with a less documented safety profile. Ethosuximide, zonisamide and the continue use of clonazepam and diazepam are contraindicated during breastfeeding.

CONCLUSIONS

Although the current available advice on the use of AEDs during breastfeeding, given by different accredited sources, present some contradictions, most AEDs can be considered safe according to our review.

Oxcarbazepine versus phenytoin monotherapy for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review published in The Cochrane Library 2006, Issue 2.Worldwide, phenytoin is a commonly used antiepileptic drug. For the newer drugs such as oxcarbazepine, it is important to know how they compare with standard treatments.

OBJECTIVES

To review the best evidence comparing oxcarbazepine and phenytoin when used as monotherapy in participants with partial onset seizures or generalised tonic-clonic seizures with or without other generalised seizure types.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register (22 January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 12) and MEDLINE (1946 to 22 January 2013). We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials in children or adults with partial onset seizures or generalised onset tonic-clonic seizures with a comparison of oxcarbazepine monotherapy with phenytoin monotherapy.

DATA COLLECTION AND ANALYSIS

This was an individual participant data review. Outcomes were time to (a) treatment withdrawal (b) 12-month remission (c) six-month remission and (d) first seizure post randomisation. We used Cox proportional hazards models to obtain study-specific estimates of hazard ratios (HR) with 95% confidence intervals (CI) with the generic inverse variance method used to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

Individual participant data were available for 480 out of 517 participants (93%) from three included trials. For remission outcomes, a HR > 1 indicates an advantage to phenytoin and for first seizure and withdrawal outcomes a HR > 1 indicates an advantage to oxcarbazepine.The main overall results (pooled HR, 95% CI) were: (i) time to withdrawal of allocated treatment 1.65 (1.08 to 2.52), (ii) time to 12-month remission 0.92 (0.68 to 1.24), (iii) time to six-month remission 0.90 (0.70 to 1.15), (iv) time to first seizure 1.07 (0.83 to 1.39). Results indicate a statistically significant advantage for oxcarbazepine over phenytoin for time to treatment withdrawal, but insufficient evidence to suggest a difference between the drugs for other outcomes. By epilepsy type, there is no significant advantage for either drug for generalised epilepsy, however there is a significant advantage for partial epilepsy with oxcarbazepine for time to treatment withdrawal (HR 1.95; 95% CI 1.15 to 3.33).

AUTHORS' CONCLUSIONS

For participants with partial onset seizures oxcarbazepine is significantly less likely to be withdrawn, but current data do not allow a statement as to whether oxcarbazepine is equivalent, superior or inferior to phenytoin in terms of seizure control. However, the design of the studies may have biased seizure outcomes and misclassification of epilepsy type may have biased withdrawal rates.

The safety and tolerability of newer antiepileptic drugs in children and adolescents

Childhood epilepsy continues to be intractable in more than 25% of patients diagnosed with epilepsy. The introduction of new anti-epileptic drugs (AEDs) provides more options for treatment of children with epilepsy. We review the safety and tolerability of seven new AEDs (levetiracetam, lamotrigine, oxcarbazepine, rufinamide, topiramate, vigabatrin and zonisamide) focusing on their side effect profiles and safety in children and adolescents. Many considerations that are specific for children such as the impact of AEDs on the developing brain are not addressed during the development of new AEDs. They are usually approved as adjunctive therapies based upon clinical trials involving adult patients with partial epilepsy. However, 2 of the AEDs reviewed here (rufinamide and vigabatrin) have FDA approval in the U.S. for specific Pediatric epilepsy syndromes, which are discussed below. The Pediatrician or Neurologists decision on the use of a new AED is an evolutionary process largely dependent on the patient characteristics, personal/peer experiences and literature about efficacy and safety profiles of these medications. Evidence based guidelines are limited due to a lack of randomized controlled trials involving pediatric patients for many of these new AEDs.

Effects of chronic treatment with valproate and oxcarbazepine on testicular development in rats

PURPOSE

The aim of this study was to examine the potential effects of valproate (VPA) and oxcarbazepine (OXC) on testicular development in rats.

METHODS

Forty-two Wistar rats were randomly divided into three groups of 14 rats each. Each group received the following via gavage over 90 days: group 1, tap water (control group); group 2, VPA (300mg/kg/day); group 3, OXC (100mg/kg/day). After sacrifice, body, testicular and epididymidis weights were measured. Testes were sampled, fixed and processed, and quantitative morphometric analysis of Sertoli cells, spermatocytes and spermatids was performed in stages II, V and XII by histopathological examination. Immunohistochemical staining was performed to transform growth factor beta 1 (TGF-β1) and p53, and the apoptotic index was assessed using the TUNEL method.

RESULTS

Testis and relative testis weights were significantly lower in the VPA group compared to the control group (p<0.05). Spermatogonia, pachytene spermatocyte and round spermatocyte numbers decreased in all stages in both the VPA and OXC groups compared to the control group, though this was not statistically significant (p>0.05). Apoptotic cell counts and p53 immunoreaction were significantly high and TGF-β1 expression was significantly lower in the VPA group compared to that of the control group (p<0.05). In the OXC group, p53 immunoreaction and TGF-β1 expression decreased compared to the control group, but this difference did not attain statistical significance (p>0.05).

CONCLUSIONS

Our results show that VPA treatment from prepuberty to adulthood significantly negatively affects spermatogenesis, not only by reducing testicular weight, but also by increasing apoptotic death and p53 and decreasing TGF-β1 activation. OXC has a minimal side effect on testicular development.

Is breast-feeding of infants advisable for epileptic mothers taking antiepileptic drugs?

Epilepsy is a relatively common maternal complication affecting 0.3-0.5% of pregnant women. For most mothers with epilepsy, the use of antiepileptic drugs (AED) is unavoidable, even during pregnancy and lactation. Therefore, the fetus is indirectly exposed to AED via the placenta and breast milk. AED are also prescribed for female patients with other diseases, such as bipolar disorders. In clinical settings, physicians are frequently questioned whether or not women patients taking AED should breast-feed their offspring. Thus, it is necessary to establish an optimum AED regimen for women taking AED, in particular for those with epilepsy during pregnancy and lactation. In this article, we critically review the effects of AED on infants via breast milk and attempt to provide suggestions for clinicians regarding these effects during breast-feeding, based on the data of transplacental passage of AED, breast milk concentration/maternal serum concentration ratios, AED metabolism in infants and the effects of AED in breast milk on infants.

Use of second-generation antiepileptic drugs in the pediatric population

Epilepsy is common in the pediatric population. Nine second-generation antiepileptic drugs have been approved in the US for use in epilepsy over the past 15 years: felbamate, gabapentin, lamotrigine, topiramate, tiagabine, levetiracetam, oxcarbazepine, zonisamide, and pregabalin. Their use in pediatric patients is fairly widespread, despite most of these agents not having US FDA indications for use. Felbamate and gabapentin were the first two second-generation antiepileptic drugs to be approved in the US. Felbamate use has been limited because of the occurrence of hepatotoxicity and aplastic anemia. Although gabapentin is a fairly well tolerated antiepileptic drug, its use has also been limited as a result of inconsistent efficacy and concern about seizure exacerbation. Lamotrigine and topiramate are broad-spectrum antiepileptic drugs with efficacy in a wide variety of seizure types. Both agents have some tolerability concerns: rash with lamotrigine and neuropsychiatric events with topiramate. There are very little data on tiagabine use in children, but this agent appears to be effective and to have a good tolerability profile. Levetiracetam is a second-generation antiepileptic agent that is available intravenously. Considering its good efficacy, fast onset of action, and low incidence of serious adverse effects, its use in the acute setting could potentially increase. Oxcarbazepine and zonisamide have been relatively well studied in pediatric seizure patients, including use as monotherapy. Both agents have demonstrated good efficacy and tolerability for patients as young as 1 month old. Vigabatrin and rufinamide are currently not available in the US, but have been shown to have some success in other countries. Pregabalin is the newest antiepileptic agent, but lacks pediatric data currently.

Interference by carbamazepine and oxcarbazepine with serum- and urine-screening assays for tricyclic antidepressants

OBJECTIVE

The purpose of this work was to evaluate the potential cross-reactivity of 2 antiepileptic medications containing 3-ringed structures, namely, carbamazepine and oxcarbazepine, with screening assays for tricyclic antidepressants.

METHODS

A cross-sectional study of 52 patients between 3 and 19 years of age who had been prescribed either carbamazepine or oxcarbazepine was conducted. A serum fluorescence-polarized immunoassay and a urine enzyme-linked immunoassay were used. The serum carbamazepine or oxcarbazepine level was measured. Gas chromatography/mass spectrometry, a confirmatory test for tricyclic antidepressant detection, was subsequently performed on the serum specimen.

RESULTS

A linear dependency on medication level was observed with the serum fluorescence-polarized immunoassay assay. This relationship was stronger for carbamazepine (4.2 microg/L tricyclic antidepressant detected per microgram/liter of carbamazepine) than for oxcarbazepine (0.7 microg/L tricyclic antidepressant detected per milligram/liter). At higher carbamazepine levels (8.0-11.6 mg/L), 12 of 13 patients had a positive serum fluorescence-polarized immunoassay result; at lower levels (0.1-7.9 mg/L), only 1 of 20 had a positive result. None of the patients who were receiving oxcarbazepine showed significant tricyclic antidepressant activity on either assay.

CONCLUSIONS

Carbamazepine interferes at a statistically significant level with serum fluorescence-polarized immunoassay assay and in a dose-dependent fashion. Neither carbamazepine nor oxcarbazepine exhibit significant tricyclic antidepressant activity on urine enzyme-linked immunoassay assay.

Open prospective study on oxcarbazepine in epilepsy in children: A preliminary report

PURPOSE

To evaluate the long-term efficacy, tolerability, and safety of oxcarbazepine (OXC) in children with epilepsy.

METHODS

We enrolled 36 patients (median age 7.75) with new diagnosis of partial epilepsy in an open prospective study. All type of epilepsy were included: 25 patients were affected by idiopathic epilepsy, eight by symptomatic epilepsy and three by cryptogenic epilepsy. Patients were then scheduled to come back for controls at 3 months (T1), 12 months (T2) and 24 months (T3) after the beginning of OXC-monotherapy (T0). At each control we evaluated patients through their seizure diary, a questionnaire on side effects, their level of 10-monohydroxy (MHD) metabolite and laboratory analysis.

RESULTS

At T1, 21/36 patients (58.3%) were seizure-free, 3/36 patients (8.3%) showed an improvement higher than 50%, 3/36 (8.3%) lower than 50%, while 2/36 worsened (5.6%). In 7/36 (19.5%) patients, no improvement was reported. At T2 13/18 patients (72.2%) were seizure-free, 1/18 showed a response to therapy higher than 50% while 2/18 worsened (11%). In two patients no improvement was reported. A correspondence between MHD plasmatic levels and clinical response (r=0.49; p<0.05) was only registered at T1. An EEG normalization was observed in 25% of cases. Side effects were reported in 25% of cases, but symptoms progressively disappeared at follow-up.

CONCLUSIONS

We can therefore conclude that OXC can be considered, for its efficacy and safety, as a first line drug in children with epilepsy.

Modern antiepileptic drugs: guidelines and beyond

PURPOSE OF REVIEW

Ten antiepileptic drugs have been licensed since 1990. Their usage will be briefly reviewed focusing on new data and inclusion in guidelines. The hypotheses exploring the underlying basis of pharmacoresistance will be presented.

RECENT FINDINGS

Lamotrigine, gabapentin, topiramate, and oxcarbazepine are available for use as monotherapy in many countries following comparative studies with older antiepileptic drugs. Zonisamide and pregabalin have recently obtained licences as adjuvant therapy in the US and Europe for partial epilepsy with or without secondary generalization. The UK National Institute for Clinical Excellence guideline has advised, largely based on cost, against the routine use of modern antiepileptic drugs, except when older drugs have failed or are contraindicated. This contrasts with the US guidelines which are less conservative. Surgically resected specimens from patients with refractory epilepsy have led to the development of two hypotheses to explain pharmacoresistant epilepsy.

SUMMARY

The introduction of 10 new antiepileptic drugs has provided greater choice for patients and doctors, although evidence in support of their superiority over the older drugs is sparse. This has led to conflicting advice in guidelines. Recent developments in the understanding of pharmacoresistance may explain the relatively high incidence of refractory epilepsy.

Oxcarbazepine in painful diabetic neuropathy: results of a dose-ranging study

OBJECTIVES

To evaluate the efficacy and safety of oxcarbazepine in patients with diabetic neuropathy in a multicenter, double-blind, placebo-controlled, dose-ranging 16-week study.

METHODS

A total of 347 patients were randomized to oxcarbazepine 600 mg/day (n = 83), 1,200 mg/day (n = 87), 1,800 mg/day (n = 88), or placebo (n = 89). The primary efficacy variable was change in mean visual analog scale (VAS) score from baseline to the last week of the study.

RESULTS

No difference between any oxcarbazepine group and the placebo group was noted for the primary efficacy variable. Both the 1,200- and 1,800-mg/day groups showed a trend toward statistical significance (P = 0.101, P = 0.096, respectively). Statistically significant differences were found between the oxcarbazepine 1,200-mg/day (P = 0.038) and 1,800-mg/day (P = 0.005) groups and placebo in the overall mean weekly VAS scores for the entire double-blind treatment phase.

CONCLUSIONS

Although the primary efficacy variable did not reach statistical significance, patients taking oxcarbazepine 1,200 and 1,800 mg/day showed improvements in VAS scores compared with placebo. Oxcarbazepine may provide clinically meaningful pain relief in patients with painful diabetic neuropathy.

Long-term use of oxcarbazepine oral suspension in childhood epilepsy: open-label study

Studies designed specifically for the pediatric population are needed to assess the tolerability and safety of the new antiepileptic drugs. The purpose of this study was to document the safety, ease of dosing, and acceptance of oxcarbazepine oral suspension in pediatric patients in monotherapy and polytherapy. A prospective, multicenter, open-label study was conducted at the neurology services of three pediatric university hospitals over 12 months. After obtaining signed informed consent, we enrolled a series of 62 patients with epilepsy aged between 2 months and 14 years who began oxcarbazepine treatment in monotherapy or in combination with other antiepileptic drugs to assess the seizure frequency, safety (adverse events), and acceptance of the pharmaceutical form by the patient's family. Fifty patients (80.6%) reduced seizures by at least 50%, 44 (71%) saw a reduction in seizure frequency of over 75%, and 29 (46.8%) were seizure free at the end of the study. The difference in the number of seizures before and after the study was statistically significant, both overall and by type of pathology. Adverse events occurred in four patients (6.4%) and required withdrawal of the drug in two cases (skin rash); three patients (4.8%) withdrew for inefficacy. Five patients (8.1%) withdrew from the treatment. We concluded that, in this series of patients, oxcarbazepine in oral suspension form was seen to help reduce seizure frequency, to have few side effects, and to be accepted by parents and patients.

Oxcarbazepine in the treatment of child psychiatric disorders: a retrospective chart review

Though not considered a first-line treatment, oxcarbazepine has become an option in the expanding effort to ameliorate severely dysregulated mood and behavioral symptoms in youth. Like most pharmaceuticals in child and adolescent psychiatry, oxcarbazepine is not U.S. Food and Drug Administration (FDA)-approved for the treatment of psychiatric disorders. A search of the world literature found a single case report pertaining to this topic. This paper is a chart review of 14 children and adolescents treated with oxcarbazepine who presented with moderate to severe problems with anger and irritability associated with a range of Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) diagnoses. A majority (70%) of patients was treatment-resistant to prior psychopharmacologic efforts, and 70% were receiving combined treatment with other agents in addition to oxcarbazepine. Moderate clinical global improvement was reported in 50% of patients receiving oxcarbazepine; tolerability was good in 86%.

Oxcarbazepine in infants and young children with partial seizures

In this open-label study, the safety, tolerability, and pharmacokinetics of oxcarbazepine as monotherapy or adjunctive therapy were studied in infants and young children with partial seizures. In a 30-day treatment phase, oxcarbazepine was titrated from 10 mg/kg/day to 60 mg/kg/day. Blood samples for analysis of the oxcarbazepine metabolite, the 10-monohydroxy derivative (MHD), were obtained at regular intervals. Patients completing the treatment phase entered a 6-month extension phase. Safety and tolerability were assessed throughout the study. Twenty-four patients (mean [range] age, 20.4 [2-45] months) were enrolled. Nineteen (79%) patients completed the treatment phase and, together with one patient who discontinued prematurely during the treatment phase, entered the extension phase. Thirteen of 20 (65%) patients completed the extension phase. The most common adverse events were pyrexia, ear infection, and irritability. Whether patients (n = 23) received enzyme-inducing antiepileptic drugs or not, MHD concentrations were consistent with those predicted from a linear, one-compartment, population-pharmacokinetic model based on a model previously fitted for 3- to 17-year-old children. Oxcarbazepine was safe and well tolerated in infants and young children. The pharmacokinetic profile of MHD was predicted by extension of a model based on older children.

Safety of the newer antiepileptic drug oxcarbazepine during pregnancy

OBJECTIVE

Seizure control in pregnant women with epilepsy is vital, as maternal seizures may have deleterious consequences. The treatment of pregnant women with epilepsy is, however, complicated by the teratogenicity of older antiepileptic drugs (AEDs). In this review, the safety of the newer AED oxcarbazepine during pregnancy is assessed based on published pregnancy outcome data. Other relevant safety issues, such as oxcarbazepine pharmacokinetics during pregnancy and the compatibility of oxcarbazepine treatment with breastfeeding, are also discussed.

METHODS

Literature searches of the following databases were performed: MEDLINE, EMBASE, eNova, NOWIMA (an internal Novartis Germany database), Derwent Drug File, SciSearch and BIOSIS. Identified publications were examined for original data reporting rates of foetal malformation following maternal exposure to oxcarbazepine as monotherapy or adjunctive therapy.

RESULTS

Relevant publications reporting data from the worldwide Novartis safety database and pregnancy registries or study centres in six countries were identified. A total of 248 pregnancies involving maternal exposure to oxcarbazepine monotherapy and 61 involving adjunctive therapy were reported. There were six malformations among the monotherapy group, equating to a malformation rate of 2.4% (6/248). The malformation rate reported in the general population is 2-4%. There were four malformations associated with oxcarbazepine adjunctive therapy, equating to a malformation rate of 6.6% (4/61).

CONCLUSIONS

This literature review suggests that, compared with newborns in the general population, the newborns of women receiving oxcarbazepine monotherapy during pregnancy do not appear to show an increased risk for malformations. However, the number of pregnancies involving maternal exposure to oxcarbazepine identified by this review is not sufficient to draw definitive conclusions. Additional information from large-scale pregnancy registries is required to confirm the safety profile of oxcarbazepine as monotherapy or adjunctive therapy during pregnancy.

10-Hydroxycarbazepine Serum Concentration-to-Oxcarbazepine Dose Ratio

This study was done to evaluate the association between patient age and the concomitant use of enzyme-inducing antiepileptic drugs (AEDs) and oxcarbazepine (OXC) concentration-to-dose ratio (CDR) by a multivariate analysis. The influence of patient age and concomitant AEDs on the trough steady-state serum concentration of 10-hydroxycarbazepine (OHC) normalized to 1 mg/kg body weight of OXC or concentration-to-dose ratio (OHC-OXC-CDR) was assessed by analysis of covariance. Samples were collected from 106 patients (90% outpatients), aged 1-80, who were receiving OXC either alone (n = 41) or in combination with other AEDs (n = 65). The average OHC-OXC CDR was 0.70 +/- 0.26 (mean +/- SD). Analysis of covariance showed that patient age was influential (P < 0.001) and that there was a difference between the noninducers group (OXC or OXC + lamotrigine, topiramate, or valproate) and the inducers group (OXC + phenobarbital or phenytoin) (P < 0.001). The OHC-OXC CDR increased with age (r = 0.14, P < 0.001) and was approximately 48% lower in children aged 6 or less than in patients over 45, and approximately 32% lower in the inducers group than in patients receiving OXC alone. The correlation between OHC-OXC CDR and the age of the patients concerned with OXC alone was r = 0.48, P < 0.001. In the noninducers group the OHC-OXC CDR was 0.59 +/- 0.24 in patients aged 11 or less (n = 16), and 0.81 +/- 0.23 in patients over 11 years (n = 62). In the inducers group it was 0.25 +/- 0.11 in patients aged 11 or less (n = 3) and 0.57 +/- 0.18 in patients over the age of 11 (n = 25). The OHC-OXC CDR increased with patient age and decreased in the presence of enzyme-inducing AEDs in epileptic patients chronically treated with OXC. These influences may be clinically relevant, and, therefore, patient age and the presence of inducers should be considered in estimating either compliance or the OXC dose needed to achieve a desired OHC concentration.

New drugs for the treatment of epilepsy: a practical approach

The availability of new antiepileptic drugs has broadened the spectrum of medical treatment options in epilepsy. The new agents, together with established drugs, offer substantial choice for doctors treating patients with focal or generalised epilepsy. The newer antiepileptic drugs are not necessarily more effective but usually better tolerated than the traditional agents, mainly because of favourable pharmacokinetic profiles and fewer interactions. Because treatment options have increased, drug therapy can now be tailored to the requirements of individual patients. Nevertheless, significant safety and efficacy issues continue to exist and there is a need for the development of even better agents. This review describes the clinical use of the new antiepileptic drugs, but focuses in particular on monotherapy, the treatment of generalised seizures, teratogenicity, and the cognitive side effect profile of the newer compounds.