Lack of Pharmacokinetic Interaction of Levetiracetam on Carbamazepine, Valproic Acid, Topiramate, and Lamotrigine in Children with Epilepsy

Adult and pediatric physiologically-based biopharmaceutics modeling to explain lamotrigine immediate release absorption process

Physiologically-based biopharmaceutics modeling (PBBM) has potential to accelerate the development of new drug and formulations. An important application of PBBM is for special populations such as pediatrics that have pharmacokinetics dependent on the maturation process. Lamotrigine (LTG) is a Biopharmaceutics Classification System (BCS) II drug and is widely prescribed. Therefore, the goal of this study was to assess the biopharmaceutics risk of the low-soluble drug LTG when the ontogeny on gastrointestinal tract (GIT) physiological parameters are considered. An oral physiologically-based pharmacokinetic model and a PBBM were developed and verified using GastroPlus™ software for both adults and children (2-12 years old, 12-52 kg). The biopharmaceutics properties and GIT physiological parameters were evaluated by sensitivity analysis. High doses were simulated assuming a worst case scenario, that is, the dose of 200 mg for adults and 5 mg/kg (up to the maximum of 200 mg) for 2-year-old children. Although several authors have suggested that ontogeny may have an effect on gastrointestinal fluid volume, our study found no evidence of interference between fluid and dose volumes with in vivo dissolution of LTG. The most impactful parameter was found to be the gastric transit time. Therefore, the hypothesis is developed to examine whether LTG exhibits characteristics of a BCS II classification in vitro while showing BCS I-like behavior in vivo. This hypothesis could act as a base for conducting novel studies on model-informed precision dosing, tailored to specific populations and clinical conditions. In addition, it could be instrumental in assessing the influence of various release profiles on in vivo performance for both adult and pediatric populations.

Dosage, time, and polytherapy dependent effects of different levetiracetam regimens on cognitive function

OBJECTIVE

Cognitive impairment is a potential drawback of antiseizure medications. This study aimed to evaluate the impact of different levetiracetam drug regimens on cognitive function.

METHODS

A retrospective analysis identified 221 patients diagnosed with seizures who underwent cognitive screening. Patients were categorized into four groups: no medications, non-levetiracetam medications, high and low dose levetiracetam. Composite scores determined low and high levetiracetam groups whereby one point was added for each increment in dosage, duration since uptake, and concurrent anti-seizure medication. Variables known to affect cognition were recorded and classified as demographic, seizure-related, diagnosis-related, and psychopathology. Logistic regression was used to identify variables associated with cognitive scores below cut-off.

RESULTS

Multivariable analysis found being male, non-active in the community, less than 12 years of education, left temporal lobe epilepsy, high seizure frequency, and depression were associated with poor cognitive performance. In a final regression analysis, the high levetiracetam group exhibited a 4.5-fold higher likelihood of scoring below cut-off than the medication-free group (OR 4.5, CI 1.5-13.6, p<.08). Depression (OR 2.1, CI 1.1-3.9, p<.03), being male (OR 2.2, CI 1.1-4.3, p<.02), and not being active in the community (OR 3.8, 1.6-8.7, p <.003) remained significant contributors to the model. Language (p<.05), attention (p<.05), and delayed recall (p<.001) were the most affected cognitive domains.

SIGNIFICANCE

When taken in small doses, for brief periods as monotherapy, levetiracetam minimally influences cognition. At higher doses, as part of long-term seizure management, in conjunction with multiple ASMs, LEV is associated with cognitive impairment.

Development and Validation of Physiologically Based Pharmacokinetic Model of Levetiracetam to Predict Exposure and Dose Optimization in Pediatrics

Levetiracetam (Lev) is an antiepileptic drug that has been increasingly used in the epilepsy pediatric population in recent years, but its pharmacokinetic behavior in pediatric population needs to be characterized clearly. Clinical trials for the pediatric drug remain difficult to conduct due to ethical and practical factors. The purpose of this study was to use the physiologically based pharmacokinetic (PBPK) model to predict changes in plasma exposure of Lev in pediatric patients and to provide recommendations for dose adjustment. A PBPK model of Lev in adults was developed using PK-Sim® software and extrapolated to the entire age range of the pediatric population. The model was evaluated using clinical pharmacokinetic data. The results showed the good fit between predictions and observations of the adult and pediatric models. The recommended doses for neonates, infants and children are 0.78, 1.67 and 1.22 times that of adults, respectively. Moreover, at the same dose, plasma exposure in adolescents was similar to that of adults. The PBPK models of Lev for adults and pediatrics were successfully developed and validated to provide a reference for the rational administration of drugs in the pediatric population.

Population pharmacokinetics of topiramate in Chinese children with epilepsy

OBJECTIVE

Topiramate, a broad-spectrum antiepileptic drug, exhibits substantial inter-individual variability in both its pharmacokinetics and therapeutic response. The aim of this study was to investigate the influence of patient characteristics and genetic variants on topiramate clearance using population pharmacokinetic (PPK) models in a cohort of Chinese pediatric patients with epilepsy.

METHOD

The PPK model was constructed using a nonlinear mixed-effects modeling approach, utilizing a dataset comprising 236 plasma concentrations of topiramate obtained from 181 pediatric patients with epilepsy. A one-compartment model combined with a proportional residual model was employed to characterize the pharmacokinetics of topiramate. Covariate analysis was performed using forward addition and backward elimination to assess the influence of covariates on the model parameters. The model was thoroughly evaluated through goodness-of-fit analysis, bootstrap, visual predictive checks, and normalized prediction distribution errors. Monte Carlo simulations were utilized to devise topiramate dosing strategies.

RESULT

In the final PPK models of topiramate, body weight, co-administration with oxcarbazepine, and a combined genotype of GKIR1-UGT (GRIK1 rs2832407, UGT2B7 rs7439366, and UGT1A1 rs4148324) were identified as significant covariates affecting the clearance (CL). The clearance was estimated using the formulas CL (L/h) = 0.44 × (BW⁄11.7)0.82 × eOXC for the model without genetic variants and CL (L/h) = 0.49 × (BW⁄11.7)0.81 × eOXC × eGRIK1-UGT for the model incorporating genetic variants. The volume of distribution (Vd) was estimated using the formulas Vd (L) = 6.6 × (BW⁄11.7). The precision of all estimated parameters was acceptable. Furthermore, the model demonstrated good predictability, exhibiting stability and effectiveness in describing the pharmacokinetics of topiramate.

CONCLUSION

The clearance of topiramate in pediatric patients with epilepsy may be subject to the influence of factors such as body weight, co-administration with oxcarbazepine, and genetic polymorphism. In this study, PPK models were developed to better understand and account for these factors, thereby improving the precision and individualization of topiramate therapy in children with epilepsy.

Lamotrigine induced priapism in children: case analysis and literature review

Lamotrigine is an antiepileptic drug that can be used to control many types of seizures as a single-agent or an add-on therapy in patients over 2 years of age. In addition to common adverse reactions, this current case report describes a paediatric male patient with a rare side-effect of persistent penile erectile due to lamotrigine. Previous studies have shown that it can improve sexual function in adult male patients. This patient suffered from refractory epilepsy and pneumonia. He had taken a variety of antiepileptic drugs for a long time and developed priapism after the dosage of lamotrigine had been increased. The priapism improved after drug withdrawal and sedation. Further research is needed to elucidate the mechanism of this rare side-effect.

Pharmacokinetic considerations surrounding the use of levetiracetam for seizure prophylaxis in neurocritical care - an overview

INTRODUCTION

Levetiracetam (LEV) is one of the most widely used anti-seizure medications (ASMs) in clinical practice. This is due both to a different mechanism of action when compared to other ASMs and its easy handling. Indeed, because of its interesting pharmacokinetic properties, it is often used outside of the labelled indications, notably in the neurocritical setting as prophylaxis of epileptic seizures.

AREAS COVERED

A literature search was conducted and the most relevant studies on the pharmacokinetic properties of LEV were selected by two independent investigators. Current evidence on the use of ASM prophylaxis in the neurocritical setting was also reviewed, highlighting and discussing the strengths and limits of LEV as drug of choice for anti-epileptic prophylaxis in this scenario.

EXPERT OPINION

LEV has a "near-ideal" pharmacokinetic profile, which makes it an attractive drug for ASM prophylaxis in neurocritical care. However, current recommendations restrict ASMs prophylaxis to very selected circumstances and the role of LEV is marginal. Moreover, studies are generally designed to compare LEV versus phenytoin, whereas studies comparing LEV versus placebo are lacking. Further randomized trials will be needed to better elucidate LEV utility and its neuroprotective role in the neurocritical setting.

The use of prophylactic antiepileptic medication and driving restrictions for craniotomies among Australian and New Zealand neurosurgeons

Prophylactic antiepileptic drug (pAED) use for craniotomy surgery is currently not supported in literature [1-5] except possibly in traumatic brain injury (TBI) [6]. Post craniotomy driving restrictions using the Austroad guidelines are based upon literature on TBI and not specifically craniotomy [16-18]. This study was to review Australian and New Zealand neurosurgeons on their use of pAED and advice on driving restrictions post craniotomy surgery. A voluntary and anonymous survey link was distributed to the members of the Neurosurgical Society of Australasia (NSA) through the NSA newsletter. The survey was available on the SurveyMonkey platform in the year 2021 August to December. Questions regarding the use of pAED and duration of driving restrictions were presented to survey participants. Sixty-one (26 %) out of 231 neurosurgeons responded to the survey. Thirty-six percent of respondents stated that they prescribed pAEDs regularly whilst thirty-two percent of respondents did not routinely prescribe pAEDs for craniotomy surgery. Driving restrictions varied but the most common driving restriction post craniotomy surgery was 6 months. There were divided opinions among NSA members in regards to pAED use and driving restrictions. The rationale for pAED use and prolonged driving restrictions for craniotomy surgery needs to be re-evaluated with current literature. The significant effect this may have on the well-being and quality life of patients need to be considered before prescribing pAEDs or long driving restrictions.

Orally disintegrating tablet containing carbamazepine and levetiracetam: formulation and in vitro and in vivo characterization

This study aimed to prepare and characterize the orally disintegrating tablet (ODT) formulations containing the combination of levetiracetam (LEV) and carbamazepine (CBZ) (CBZ + LEV combination) for the treatment of epilepsy. The ODT formulations were prepared using the lyophilization (L) and direct compression (DC) methods. The flowability of the mixed powders used for DC formulation was evaluated. The quality control tests for the ODTs were performed. Also, the antiepileptic effects of pure drugs, their combination, and the suspension of CBZ + LEV-DC-ODT formulation were evaluated in the rats with pentylenetetrazole (PTZ)-induced epilepsy model. The obtained results for the mixed powders of the DC formulation (angle of repose: 26.18 ± 0.794°; compressibility index: 15.24 ± 0.764%) suggest that the flow properties of the powder blend were suitable for the preparation of CBZ + LEV-ODT using DC method. The mean values of diameter and hardness of L-ODTs and DC-ODTs were found to be 16.87 mm and 16.18 mm and 11.96 N and 30.11 N, respectively. The friability of both formulations was <1%. Both formulations were disintegrated in seconds. Drugs in L-ODT had faster dissolution than those in DC-ODT. Compared to the seizure scores obtained for the groups treated with LEV or CBZ, generally, there was a higher decrease in seizure scores in the groups treated with CBZ + LEV combination or the suspension of CBZ + LEV-DC-ODTs. Consequently, the ODT formulations containing the CBZ + LEV combination might be beneficial in the treatment of epilepsy.

Levetiracetam Therapeutic Drug Monitoring in a Large Cohort of Korean Epileptic Patients

Levetiracetam is a new antiepileptic drug (AED) used for treating and preventing partial or generalized seizures. The usefulness of levetiracetam therapeutic drug monitoring (TDM) is related to inter- or intra-individual pharmacokinetic variability, drug interactions, and patient noncompliance. We aimed to investigate the levetiracetam TDM status in Korean epilepsy patients. Serum trough levetiracetam concentrations were measured using liquid chromatography–tandem mass spectrometry in 710 samples from 550 patients. The median (range) daily and weight-adjusted levetiracetam doses were 1500 (20–5000) mg and 25.5 (3.03–133.0) mg/kg, respectively. Patients on levetiracetam monotherapy constituted only 19.5% of the population, while 30.1% were on co-medication with valproate and 56.0% with enzyme-inducing AEDs (EIAEDs). Observed levetiracetam concentrations were widely distributed, ranging 0.8–95 mg/L, with a median of 17.3 mg/L. Levetiracetam concentrations were therapeutic, supra-therapeutic, and sub-therapeutic in 58.5% (n = 393), 11.6% (n = 78), and 29.9% (n = 201) of samples, respectively. There was a strong correlation between weight-adjusted levetiracetam dosage and concentrations (ρ = 0.6896, p < 0.0001). In this large-scale clinical study, a large inter-individual difference in levetiracetam pharmacokinetics was observed, and levetiracetam concentrations were influenced by EIAEDs. For individual dose adjustments and monitoring compliance, routine levetiracetam TDM is needed in epilepsy patients.

The influence of concomitant antiepileptic drugs on lamotrigine serum concentrations in Northwest Chinese Han population with epilepsy

Objective

The aims of this study were to identify the influencing factors such as gender, age, dose and combinations of other antiepileptic drugs (AEDs), especially in triple combinations on the pharmacokinetic of Lamotrigine (LTG) in epilepsy patients of Northwest Chinese Han population.

Methods

Data of the LTG concentration and clinical information were analyzed retrospectively from a therapeutic drug monitoring (TDM) database at the Clinical Pharmacy Laboratory of Xi’an Central Hospital between January 1, 2016 and January 1, 2018. The independent-sample t-test, one-way ANOVA analysis and Bonferroni and Tamhane T3 post-hoc test, the stepwise multivariate regression analysis were adopted by IBM SPSS, version 22.0.

Results

226 serum samples met the inclusion criteria and were evaluated. The mean LTG serum concentration was 5.48±3.83 μg/mL. There were no gender differences (P = 0.64), and there were no significant effects by age on LTG serum concentration after age stratification (3–14 years old, 14-45 years old, 45–59 years old) (P = 0.05). Multiple regression analysis showed that the daily LTG dose and co-administration of other AEDs significantly affected LTG serum concentrations. Combination with enzyme-inducer AEDs, the mean steady-state LTG concentration could be decreased by 30.73% compared with LTG monotherapy. Among enzyme-inducer AEDs, particularly strong inducer Carbamazepine (CBZ) could decrease the mean LTG concentration by 53.65%, but weak inducer AEDs such as Oxcarbazepine (OXC) and Topiramate (TPM) had no effect, Valproic acid (VPA) could increase the mean LTG concentration by 93.95%, and the inducer only partially compensated for the inhibitory effect of VPA in triple combination.

Conclusions

There were no significant gender and age effects, but the LTG daily dose and co-administration of other AEDs significantly affected LTG serum concentration. Combination with enzyme-inducer AEDs, especially CBZ could significantly decrease LTG serum concentrations, VPA could significantly increase LTG serum concentrations, and the inducer only partially compensated for the inhibitory effect of VPA in triple combination. In the clinical setting, these findings can help to estimate LTG concentrations and adjust dosage and evaluate adverse drug reactions.

A meta-analysis of levetiracetam for randomized placebo-controlled trials in patients with refractory epilepsy

OBJECTIVE

The objective of this study was to investigate the efficacy and safety profile of levetiracetam as add-on therapy in patients with refractory epilepsy.

METHODS

Web of Science, MEDLINE (Ovid and PubMed), Cochrane Library, EMBASE, and Google Scholar were systematically searched to identify potential eligible randomized controlled trials by two reviewers independently. Pooled estimates of risk ratios (RRs) for 50%, 75%, and 100% reduction from baseline were calculated using the fixed-effect model or random-effect model. Quality of included studies was assessed with the Cochrane Collaboration's Risk of Bias tool. Serious adverse events and withdrawals induced by interventions and the most common side effects were analyzed.

RESULTS

Seventeen trials with a total of 3,205 participants were included in this meta-analysis, including 14 trials for adulthood and three trials for children. Pooled estimates suggested that levetiracetam was an effective anti-epileptic drug at 1,000-3,000 mg/day (RR =2.00 for 1,000 mg/day, RR =2.68 for 2,000 mg/day, RR =2.18 for 3,000 mg/day) for adults and 60 mg/kg/day (RR =2.00) for children compared to placebo in terms of 50% reduction from baseline. Likewise, as for seizure freedom rate, levetiracetam had an advantage over placebo at 1,000-3,000 mg/day (RR =5.84 for 1,000 mg/day, RR =4.55 for 2,000 mg/day, RR =4.57 for 3,000 mg/day, respectively) for adults and 60 mg/kg/day (RR =4.52) for children. Regarding safety profile, patients treated with levetiracetam had significantly higher occurrence than placebo for somnolence, asthenia, dizziness, infection, nasopharyngitis, anxiety, and irritability; however, most studies reported that these adverse events were mild and transient.

CONCLUSION

Levetiracetam is an effective anti-epileptic drug for both adults and children with generalized or partial-onset refractory seizures at 1,000-3,000 or 60 mg/kg/day, with a favorable adverse event profile.

Clinical outcomes of intravenous levetiracetam treatment in patients with renal impairment

Intravenous levetiracetam has been approved for use as an antiepileptic drug, as well as in cases of status epilepticus. There are few reports that detail the clinical data and outcomes associated with this antiepileptic drug, particularly in patients with renal impairment. This was a retrospective analytical study conducted at Khon Kaen University's Srinagarind Hospital in Thailand. The study period was between January 1, 2010 and December 31, 2014. The inclusion criteria were that patents were over 15 years old, had renal impairment, and had received intravenous levetiracetam treatment. The main clinical outcomes were seizure control and mortality. Clinical outcomes were compared between those with and without status epilepticus. Mortality of patients with status epilepticus were compared in terms of seizure control and order of intravenous levetiracetam treatment. During the study period, there were 247 patients who met the study criteria. The average age of the patients was 58 years with nearly equal sex distribution. Of those, 90 patients (36.4%) had GRFs of less than 15 mL/min/1.73 m² and 60 patients (24.3%) received intravenous LEVE due to status epilepticus. The seizure control rates in the status epilepticus and non-status epilepticus groups were 36.7% and 88.7%, respectively (P<0.001). The mortality rate did not differ significantly between the two groups (33.3% vs 27.8%; P=0.418). There was no significant overall difference in mortality rate between seizure-controlled and seizure-uncontrolled patients in the status epilepticus group. In the convulsive status epilepticus group, variations in terms of treatment order of intravenous levetiracetam and seizure control resulted in no significant difference in mortality rates (P=0.311). No major side effects were detected in any patients after the intravenous levetiracetam treatment. In conclusion, intravenous levetiracetam treatment was effective and safe in patients with renal impairment.

Safety of levetiracetam among infants younger than 12 months--Results from a European multicenter observational study

BACKGROUND

There are limited data on the use of the antiepileptic drug (AED) levetiracetam for the treatment of infants.

AIM

To prospectively evaluate the safety of levetiracetam oral solution and its impact on epilepsy severity in infants with different seizure types.

METHODS

This noninterventional post-authorization safety study included patients 1-11 months of age. Patients' treatment - levetiracetam dose, and addition, withdrawal or changes in the doses of concomitant medications and AEDs - was at the discretion of the physician. The primary variable was treatment-emergent adverse events (TEAEs).

RESULTS

Of 101 infants, 75 completed and 26 discontinued the study. Mean age was 6.0 months, 50 were male, most (80%) took 1 ≥ concomitant AED and had cryptogenic or symptomatic epilepsy that was focal (38.6%) or generalized (20.8%), particularly frontal lobe epilepsy (20.0%) or West syndrome/infantile spasms (20.0%). Among known aetiologies, congenital factors (22.8%) such as dysplastic lesions or perinatal events (17.8%) were predominant. Overall, 54.5% of patients had ≥ 1 TEAE. Five patients experienced drug-related TEAEs - convulsion, irritability, somnolence and hypotonia, all listed in the product label, with the exception of hypotonia, which was reported for one patient and resolved without any change in study medication. Seven patients discontinued due to TEAEs, mainly due to infantile spasms and respiratory disorders. At study end, 71.8% of patients showed improvement in epilepsy severity, 18.8% remained stable and 9.4% showed worsening. Levetiracetam did not appear to have a negative effect on growth parameters.

CONCLUSION

In this prospective study, which included the largest number of patients in this age range so far, levetiracetam was found to be well tolerated and efficacious for the treatment of infants with epilepsy.

Clinical pharmacokinetics of new-generation antiepileptic drugs at the extremes of age: an update

Epilepsies occur across the entire age range, and their incidence peaks in the first years of life and in the elderly. Therefore, antiepileptic drugs (AEDs) are commonly used at the extremes of age. Rational prescribing in these age groups requires not only an understanding of the drugs' pharmacodynamic properties, but also careful consideration of potential age-related changes in their pharmacokinetic profile. The present article, which updates a review published in 2006 in this journal, focuses on recent findings on the pharmacokinetics of new-generation AEDs in neonates, infants, children, and the elderly. Significant new information on the pharmacokinetics of new AEDs in the perinatal period has been acquired, particularly for lamotrigine and levetiracetam. As a result of slow maturation of the enzymes involved in glucuronide conjugation, lamotrigine elimination occurs at a particularly slow rate in neonates, and becomes gradually more efficient during the first months of life. In the case of levetiracetam, elimination occurs primarily by renal excretion and is also slow at birth, but drug clearance increases rapidly thereafter and can even double within 1 week. In general, infants older than 2-3 months and children show higher drug clearance (normalized for body weight) than adults. This pattern was confirmed in recent studies that investigated the pediatric pharmacokinetics of several new AEDs, including levetiracetam, rufinamide, stiripentol, and eslicarbazepine acetate. At the other extreme of age, in the elderly, drug clearance is generally reduced compared with younger adults because of less efficient drug-metabolizing activity, decreased renal function, or both. This general pattern, described previously for several AEDs, was confirmed in recent studies on the effect of old age on the clearance of felbamate, levetiracetam, pregabalin, lacosamide, and retigabine. For those drugs which are predominantly eliminated by renal excretion, aging-related pharmacokinetic changes could be predicted by measuring creatinine clearance (CLCR). Overall, most recent findings confirm that age is a major factor influencing the pharmacokinetic profile of AEDs. However, pharmacokinetic variability at any age can be considerable, and the importance of other factors should not be disregarded. These include genetic factors, co-morbidities, and drug interactions, particularly those caused by concomitantly administered AEDs which induce or inhibit drug-metabolizing enzymes.

Clinical pharmacology and pharmacokinetics of levetiracetam

Status epilepticus and acute repetitive seizures still pose a management challenge despite the recent advances in the field of epilepsy. Parenteral formulations of old anticonvulsants are still a cornerstone in acute seizure management and are approved by the FDA. Intravenous levetiracetam (IV LEV), a second generation anticonvulsant, is approved by the FDA as an adjunctive treatment in patients 16 years or older when oral administration is not available. Data have shown that it has a unique mechanism of action, linear pharmacokinetics and no known drug interactions with other anticonvulsants. In this paper, we will review the current literature about the pharmacology and pharmacokinetics of IV LEV and the safety profile of this new anticonvulsant in acute seizure management of both adults and children.

Levetiracetam compared with valproic acid for the prevention of postoperative seizures after supratentorial tumor surgery: a retrospective chart review

INTRODUCTION

Antiepileptic drugs are commonly given for perioperative prophylaxis after brain tumor surgery, and there has been growing interest in levetiracetam, a second-generation antiepileptic drug. This retrospective study compared the seizure outcomes, side effects and durability of levetiracetam with valproic acid after a craniotomy for supratentorial brain tumors.

METHODS

Between 2009 and 2012, 282 consecutive patients with a supratentorial brain tumor underwent a craniotomy at Seoul National University Bundang Hospital. Of these patients, 51 (18.1%) and 231 (81.9%) were pre-operatively administered levetiracetam and valproic acid, respectively. The postoperative seizure outcomes (within 1 month after surgery) and the long-term side effects of both drugs were evaluated.

RESULTS

Of the 51 patients in the levetiracetam group, 4 (7.8%) experienced postoperative seizures after brain tumor surgery, and 15 (6.5%) of the 231 patients in the valproic acid group experienced postoperative seizures (p = 0.728). The long-term complication rate of the valproic acid group (26.8%; 62/231) was significantly higher than that of the levetiracetam group (9.8%; 5/51) [p = 0.010]. In the valproic acid group, 10 hepatotoxicities, 20 hyperammonemias and 10 hematologic abnormalities (6 thrombocytopenias, 3 pancytopenias, and 1 leucopenia) occurred. Moreover, 89 patients (38.5%) in the valproic acid group changed or added other anticonvulsants because of side effects or uncontrolled seizures, whereas only 9 patients (17.6%) in the levetiracetam group changed or added other anticonvulsants (p = 0.005).

CONCLUSIONS

The postoperative seizure control rates of levetiracetam and valproic acid were not statistically significantly different; however, levetiracetam may be superior to valproic acid in terms of its safety and durability after supratentorial tumor surgery.

Safety and efficacy of levetiracetam for the treatment of partial onset seizures in children from one month of age

Epilepsy is a common neurological disorder in the pediatric population, affecting up to one percent of children, and for which the mainstay of treatment is anticonvulsant medication. Despite the frequent use of anticonvulsant drugs, remarkably little is known about the safety and efficacy of most of these medications in the pediatric epilepsy population. Of 34 anticonvulsants currently approved for use by the US Food and Drug Administration (FDA), only 13 have been approved for use in children. Although infants and young children are disproportionately affected by epilepsy, there are currently only three anticonvulsant medications that have been specifically evaluated and approved for use in children younger than 2 years of age. In 2012, the FDA approved levetiracetam as an adjunctive treatment for partial onset seizures in infants and children from one month of age. Here we review the available data on levetiracetam in the pediatric epilepsy population. We first discuss the pharmacological profile of levetiracetam, including its mechanism of action, formulations and dosing, and pharmacokinetics in children. We then review the available efficacy, safety, and tolerability data in children from one month of age with partial onset seizures. We conclude that the current data leading to the approval of levetiracetam for use in infants and children with partial onset seizures is encouraging, although more work needs to be done before definitive conclusions can be drawn about the efficacy of levetiracetam across different pediatric age groups.

Levetiracetam: a review of its use in epilepsy

Levetiracetam (Keppra®, E Keppra®) is an established second-generation antiepileptic drug (AED). Worldwide, levetiracetam is most commonly approved as adjunctive treatment of partial onset seizures with or without secondary generalization; other approved indications include monotherapy treatment of partial onset seizures with or without secondary generalization, and adjunctive treatment of myoclonic seizures associated with juvenile myoclonic epilepsy and primary generalized tonic-clonic (GTC) seizures associated with idiopathic generalized epilepsy. Levetiracetam has a novel structure and unique mechanisms of action. Unlike other AEDs, the mechanisms of action of levetiracetam appear to involve neuronal binding to synaptic vesicle protein 2A, inhibiting calcium release from intraneuronal stores, opposing the activity of negative modulators of GABA- and glycin-gated currents and inhibiting excessive synchronized activity between neurons. In addition, levetiracetam inhibits N-type calcium channels. Levetiracetam is associated with rapid and complete absorption, high oral bioavailability, minimal metabolism that consists of hydrolysis of the acetamide group, and primarily renal elimination. It lacks cytochrome P450 isoenzyme-inducing potential and is not associated with clinically significant pharmacokinetic interactions with other drugs, including other AEDs. The efficacy of oral immediate-release levetiracetam in controlling seizures has been established in numerous randomized, double-blind, controlled, multicentre trials in patients with epilepsy. Adjunctive levetiracetam reduced the frequency of seizures in paediatric and adult patients with refractory partial onset seizures to a significantly greater extent than placebo. Monotherapy with levetiracetam was noninferior to that with carbamazepine controlled release in controlling seizures in patients with newly diagnosed partial onset seizures. Levetiracetam also provided seizure control relative to placebo as adjunctive therapy in patients with idiopathic generalized epilepsy with myoclonic seizures or GTC seizures. In addition, patients receiving oral levetiracetam showed improvements in measures of health-related quality of life relative to those receiving placebo. Although treatment-emergent adverse events were commonly reported in the clinical trials of levetiracetam, the overall proportion of patients who experienced at least one treatment-emergent adverse event was broadly similar in the levetiracetam and placebo treatment groups, with most events being mild to moderate in severity. Levetiracetam is not associated with cognitive impairment or drug-induced weight gain, but has been associated with behavioural adverse effects in some patients.

Age and comedications influence levetiracetam pharmacokinetics in children

The pharmacokinetics of many antiepileptic drugs differs between adults and children. The influence of age and concomitant medications on the dose/concentration ratio of levetiracetam was examined in 103 children with epilepsy. Dosing and plasma levels of levetiracetam and concomitant antiepileptic drugs were reviewed retrospectively. The dose/concentration ratio was calculated as the weight-normalized dose (mg/kg/day) divided by the steady-state trough plasma drug level, which was used as a measure of apparent oral clearance of levetiracetam. Children were classified into age groups and treatment groups: levetiracetam given with enzyme inducers (n = 24) or nonenzyme inducers (n = 69), or as monotherapy (n = 10). Levetiracetam clearance differed significantly between age groups (0-4, 5-11, and 12-17 years), i.e., the younger the child, the higher the clearance. The increase was 1.7-fold between the youngest and oldest age groups. Children on enzyme inducers exhibited significantly higher clearance (1.3-fold), compared with those on nonenzyme inducers and monotherapy. Levetiracetam did not influence the clearance of lamotrigine, valproate, topiramate, or clonazepam. In conclusion, younger age and comedication with an enzyme inducer increased levetiracetam clearance. This finding should be taken into account when treating individual patients.

[Therapeutic drug monitoring of valproate]

Valproic acid is an anticonvulsant drug available in France since 1967. It is a broad spectrum molecule indicated in various forms of epilepsy of the adult and the child, but it is also prescribed in the treatment of different other pathologies of nervous system. The divalproate sodium is indicated in the treatment of bipolar disorders. The valproic acid is marketed under various pharmaceutical forms, with different corresponding tmax values. But, whatever the administered preparation, the circulating active molecule is the ion valproate. Elimination half-life is from 11 to 20 h. Metabolization of valproate is important and represents its main route of elimination. Valpromide is comparable to a prodrug which metabolizes in valproate. The inter and intraindividual variability of the plasma concentrations are important. Several studies show a concentration-effect relationship, but two interventional trials ended in the lack of interest of the Therapeutic Drug Monitoring (TDM), although it is of current practice. However, numerous drug interactions may modify the plasma concentrations of valproate. The therapeutic range is from 50 to 100 mg/L (346-693 micromol/L). The level of proof of the interest of the TDM for this molecule was estimated in: recommended.

Intravenous levetiracetam in the management of acute seizures in children

Levetiracetam may be effective in children with acute seizures or status epilepticus. We performed a retrospective chart review of children who received intravenous levetiracetam within 30 minutes of a seizure. Seventy-three patients during a 2-year study period met our inclusion criteria. The mean (+/- S.D.) age and weight of the patients were 5.59 +/- 5.6 years (range, 1 day to 17.8 years) and 23.1 +/- 21 kg (range, 1.97-97 kg), respectively. Patients received a mean (+/- S.D.) levetiracetam dose of 29.4 +/- 13.5 mg/kg. Most children (n = 49, or 67%) received additional antiepileptic drugs to abort their seizure. Overall, the mean (+/- S.D.) total (abortive plus chronic) number of concomitant antiepileptic drugs used by the population was 2.53 +/- 1.7 (1.07 +/- 0.98 as additional abortive therapy, and 1.42 +/- 1.29 as chronic therapy). Most patients received levetiracetam for serial seizures (79%), whereas 12% and 8% manifested a single seizure or status epilepticus, respectively. Clinical effectiveness at 1, 12, 24, 48, and 72 hours after the initial levetiracetam dose constituted the primary study outcome. Eighty-nine percent of patients remained seizure-free at 1 hour. This rate decreased at each evaluation time point. Most patients (71%) were placed on maintenance levetiracetam within 24 hours of their loading dose. The predictive ability of patient and drug regimen variables in outcomes was poor. Only the number of concomitant antiepileptic drugs consistently predicted outcomes. Levetiracetam was well tolerated at the doses studied, and appears most effective in single seizure events.

Levetiracetam in childhood epilepsy

Levetiracetam is an antiepileptic drug that has been shown to be effective in various types of seizures, both partial and generalized. Although it is not yet well established because of the small number of studies, levetiracetam as both add-on therapy and monotherapy can be considered as an alternative to valproic acid in some pediatric patients. We have reviewed the available data on the efficacy, tolerability, and safety of levetiracetam in children with epilepsy. The efficacy of levetiracetam as an adjunctive therapy and as monotherapy for generalized and partial childhood epilepsies and for some types of specific epileptic syndromes of infancy and childhood (such as juvenile myoclonic epilepsy, benign rolandic epilepsy, and Jeavon syndrome) has been demonstrated in some studies. Moreover, levetiracetam may be a valuable option for children with refractory epilepsy. The reported tolerability of levetiracetam and its safety profile are favorable. Among the side effects reported, behavioral changes and even psychotic reactions seem to occur more frequently in younger patients (under 4 years of age). The onset of signs/symptoms usually occurs early, even during the titration phase, and, in many cases, at a low dosage (<20 mg/kg/day). These side effects were always observed to be reversible after discontinuation of levetiracetam. In conclusion, results from clinical trials to date suggest that levetiracetam has a full spectrum of efficacy as well as a favorable safety profile, and this drug can be considered a valuable option in the treatment of epilepsy in pediatric patients.

Intravenous levetiracetam in critically ill children with status epilepticus or acute repetitive seizures

OBJECTIVE

Intravenous (IV) levetiracetam (LEV) is approved for use in patients older than 16 years and may be useful in critically ill children, although there is little data available regarding pharmacokinetics. We aim to investigate the safety, an appropriate dosing, and efficacy of IV LEV in critically ill children.

DESIGN

We describe a cohort of critically ill children who received IV LEV for status epilepticus, including refractory or nonconvulsive status, or acute repetitive seizures.

RESULTS

There were no acute adverse effects noted. Children had temporary cessation of ongoing refractory status epilepticus, termination of ongoing nonconvulsive status epilepticus, cessation of acute repetitive seizures, or reduction in epileptiform discharges with clinical correlate.

CONCLUSIONS

IV LEV was effective in terminating status epilepticus or acute repetitive seizures and well tolerated in critically ill children. Further study is needed to elucidate the role of IV LEV in critically ill children.

Adjunctive levetiracetam in infants and young children with refractory partial-onset seizures

PURPOSE

To evaluate the efficacy and tolerability of adjunctive levetiracetam in very young children (aged 1 month to <4 years) with partial-onset seizures inadequately controlled with one or two antiepileptic drugs.

METHODS

This multicenter, double-blind, randomized, placebo-controlled study consisted of a 48-h inpatient baseline video-EEG (electroencephalography) and a 5-day inpatient treatment period (1-day up-titration; 48-h evaluation video-EEG in the last 2 days). Children who experienced at least two partial-onset seizures during the 48-h baseline video-EEG were randomized to either levetiracetam [40 mg/kg/day (age 1 to <6 months); 50 mg/kg/day (age >or=6 months to <4 years] or placebo.

RESULTS

Of 175 patients screened, 116 patients were randomized [60 levetiracetam; 56 placebo; intent-to-treat (ITT) population], and 111 completed the study. The responder rate in average daily partial-onset seizures frequency (48-h video-EEG monitoring; primary efficacy variable) was 43.1% for levetiracetam [modified ITT (mITT) = 58] versus 19.6% for placebo (mITT = 51; p=0.013), with odds ratio for response 3.11 [95% confidence interval (CI), 1.22-8.26]. The median percent reduction from baseline in average daily partial-onset seizure frequency was 43.6% for levetiracetam and 7.1% for placebo with a median difference between treatment groups of 39.2% (95% CI, 17.5-62.2; p < 0.001). In general, levetiracetam was well tolerated. Treatment-emergent adverse events were reported by 55.0% levetiracetam- and 44.6% placebo-treated patients (ITT population). The most frequently reported adverse events were somnolence (13.3% levetiracetam, 1.8% placebo) and irritability (11.7% levetiracetam, 0% placebo).

DISCUSSION

Adjunctive levetiracetam is an efficacious and well-tolerated treatment for partial-onset seizures in infants and young children.

Brivaracetam: a new drug in development for epilepsy and neuropathic pain

BACKGROUND

Epilepsy is a neurological disorder with a worldwide prevalence estimated to be 0.5-1.0% of the population. Many potent antiepileptic drugs (AED) have been used for treatment but still about 30% of patients are resistant to current AEDs. Some AEDs are also used for the treatment of neuropathic pain.

OBJECTIVE

The aim of this report is to present preclinical and clinical studies of brivaracetam (UCB-34714), a new drug developed by UCB Pharma.

METHODS

Published results of preclinical studies in several animal models of epilepsy, neuropathic pain, essential tremor and results of Phase I and II evaluations of brivaracetam have been analysed.

RESULTS/CONCLUSION

Brivaracetam represents a new mechanism of action being a ligand of synaptic vesicle protein 2A. It is undergoing Phase III evaluation after a successful Phase II programme in which was effective as an adjunctive treatment in partial-onset epilepsy (50 mg/day). It is well tolerated, without serious adverse side effects.

Modeling and simulation of intravenous levetiracetam pharmacokinetic profiles in children to evaluate dose adaptation rules

PURPOSE

To develop a pharmacokinetic model for intravenous levetiracetam in children, based on adult intravenous data and pediatric oral data.

METHODS

Data from two adult Phase-I studies in which levetiracetam was given intravenously were utilized to develop the adult population pharmacokinetic two-compartment intravenous model. After model qualification, combination with an existing pediatric one-compartment oral population pharmacokinetic model enabled simulation of twice-daily intravenous infusions of levetiracetam in children. Median and 90% confidence intervals for C(trough), C(max) (end of infusion) and AUC(tau) were simulated for 2000 children and compared to the values observed in adults.

RESULTS

The population pharmacokinetic two-compartment model successfully described intravenous levetiracetam pharmacokinetics in healthy adults. After combination with the oral pediatric population model, steady-state concentrations at the end of 15-, 30- and 60 min b.i.d. levetiracetam intravenous infusions in children were predicted to be 29-41, 17-24 and 6-13% higher than those observed after oral dosing of 30 mg/kg b.i.d. Concentrations returned to the range of oral exposures within 1h after the infusion peak. The combined model predicted that steady-state peak plasma concentrations and AUC(tau) in children receiving 30 mg/kg twice daily as 15 min intravenous infusions were within the range of predicted and observed C(max,ss) and AUC(tau )values of adults receiving 15 min intravenous infusions of 1500 mg levetiracetam.

CONCLUSIONS

The simulations suggest that levetiracetam may be administered intravenously in children as 15 min infusions.