The anti-epileptic drug levetiracetam reverses the inhibition by negative allosteric modulators of neuronal GABA- and glycine-gated currents

Development of SV2A Ligands for Epilepsy Treatment: A Review of Levetiracetam, Brivaracetam, and Padsevonil

Epilepsy is a common neurological disorder that is primarily treated with antiseizure medications (ASMs). Although dozens of ASMs are available in the clinic, approximately 30% of epileptic patients have medically refractory seizures; other limitations in most traditional ASMs include poor tolerability and drug-drug interactions. Therefore, there is an urgent need to develop alternative ASMs. Levetiracetam (LEV) is a first-line ASM that is well tolerated, has promising efficacy, and has little drug-drug interaction. Although it is widely accepted that LEV acts through a unique therapeutic target synaptic vesicle protein (SV) 2A, the molecular basis of its action remains unknown. Even so, the next-generation SV2A ligands against epilepsy based on the structure of LEV have achieved clinical success. This review highlights the research and development (R&D) process of LEV and its analogs, brivaracetam and padsevonil, to provide ideas and experience for the R&D of novel ASMs.

Behavioral and neurotransmitter changes on antiepileptic drugs treatment in the zebrafish pentylenetetrazol-induced seizure model

Epilepsy, a recurrent neurological disorder involving abnormal neurotransmitter kinetics in the brain, has emerged as a global health concern. The mechanism of epileptic seizures is thought to involve a relative imbalance between excitatory and inhibitory neurotransmitters. Despite the recent advances in clinical and basic research on the pathogenesis of epilepsy, the complex relationship between the neurotransmitter changes and behavior with and without antiepileptic drugs (AEDs) during seizures remains unclear. To investigate the effects of AEDs such as levetiracetam (LEV), carbamazepine (CBZ), and fenfluramine (FFR) on key neurotransmitters in the pentylenetetrazol (PTZ)-induced seizures in adult zebrafish, we examined the changes in glutamic acid, gamma-aminobutyric acid (GABA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), choline, acetylcholine, norepinephrine, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and adenosine. In this study, we observed that 5-HT and DA levels in the brain increased immediately after PTZ-induced seizures. Behavioral tests clearly showed that all of these AEDs suppressed the PTZ-induced seizures. Upon treatment of PTZ-induced seizures with these AEDs, CBZ decreased the glutamic acid and FFR increased the GABA levels; however, no neurotransmitter changes were observed in the brain after LEV administration. Thus, we demonstrated a series of neurotransmitter changes linked to behavioral changes during PTZ-induced epileptic seizures when LEV, CBZ, or FFR were administered. These findings will lead to a more detailed understanding of the pathogenesis of epilepsy associated with behavioral and neurotransmitter changes under AED treatment.

Real-world safety of Levetiracetam: Mining and analysis of its adverse drug reactions based on FAERS database

INTRODUCTION

Levetiracetam is a relatively new and widely utilized anti-seizure medication; however, limited information is available regarding its adverse effects. This study aims to thoroughly investigate, evaluate, and present evidence on the safety profile of Levetiracetam, relying on data from the FDA Adverse Event Reporting System (FAERS) database to facilitate informed clinical decision-making.

METHODS

We employed various statistical measures, including Reporting Odds Ratio (ROR), Proportionate Reporting Ratio (PRR), and analysis by the Medicines and Healthcare Products Regulatory Agency (MHRA), to identify signals of adverse reactions associated with Levetiracetam. Positive signals consistent with Designated Medical Event (DME) were singled out for focused comparison and discussion.

RESULTS

The analysis of 26,182 adverse events linked to Levetiracetam as the primary suspected drug revealed 692 positive signals spanning 22 System Organ Classes (SOCs). Nervous system disorders were the most frequently reported, followed by psychiatric disorders, and general disorders and administration site conditions. 11 positive signals consistent with Preferred Terms (PTs) in DME were identified, predominantly concentrated in 6 SOCs. Among these, rhabdomyolysis, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS) exhibited relatively large values of A, ROR, and Chi-squared. Additionally, PTs related to spontaneous abortion, drug interaction, urethral atresia, ventricular septal defect, and atrial septal defect showed significant strength.

CONCLUSIONS

The study indicates that Levetiracetam carries a potential risk of causing rhabdomyolysis, SJS, TEN, DRESS as well as spontaneous abortion. Signals related to drug interaction, urethral atresia, ventricular septal defect, and atrial septal defect warrant heightened attention in clinical use.

Pharmacological treatment of Tourette's syndrome: from the past to the future

Tourette's syndrome (TS) is a neuropsychiatric disease featuring tics and vocal tics, with a prevalence of approximately 1%, including 75% of the total number of male patients. TS seriously disturbs the patients' career, education, and life and brings a serious and unbearable psychological burden to the patients themselves and their families. At present, there are no specific clinical medications recommended for treating TS. Therefore, it is necessary to select the appropriate medication for symptomatic treatment based on the doctor's personal experience and the patient's symptoms, with the main goal of relieving symptoms, thus improving the patient's social skills and psychological problems. Here we conducted a comprehensive search on PubMed to review and organize the history and current status of the development of drug therapy for TS through a timeline format. We also systematically evaluated the effects of each drug for TS treatment to summarize the current problems and new research directions and to provide some ideas for clinical treatment.

Pharmacological adjuncts and transcranial magnetic stimulation-induced synaptic plasticity: a systematic review

BACKGROUND

Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation modality that has been used to study human synaptic plasticity. Leveraging work in ex vivo preparations, mechanistically informed pharmacological adjuncts to TMS have been used to improve our fundamental understanding of TMS-induced synaptic plasticity.

METHODS

We systematically reviewed the literature pairing pharmacological adjuncts with TMS plasticity-induction protocols in humans. We searched MEDLINE, PsycINFO, and Embase from 2013 to Mar. 10, 2023. Studies published before 2013 were extracted from a previous systematic review. We included studies using repetitive TMS, theta-burst stimulation, paired associative stimulation, and quadripulse stimulation paradigms in healthy and clinical populations.

RESULTS

Thirty-six studies met our inclusion criteria (28 in healthy and 8 in clinical populations). Most pharmacological agents have targeted the glutamatergic N-methyl-d-aspartate (NMDA; 15 studies) or dopamine receptors (13 studies). The NMDA receptor is necessary for TMS-induced plasticity; however, sufficiency has not been shown across protocols. Dopaminergic modulation of TMS-induced plasticity appears to be dose-dependent. The GABAergic, cholinergic, noradrenergic, and serotonergic neurotransmitter systems have small evidence bases supporting modulation of TMS-induced plasticity, as do voltage-gated calcium and sodium channels. Studies in clinical populations suggest that pharmacological adjuncts to TMS may rescue motor cortex plasticity, with implications for therapeutic applications of TMS and a promising clinical trial in depression.

LIMITATIONS

This review is limited by the predominance in the literature of studies with small sample sizes and crossover designs.

CONCLUSION

Pharmacologically enhanced TMS largely parallels findings from ex vivo preparations. As this area expands and novel targets are tested, adequately powered samples in healthy and clinical populations will inform the mechanisms of TMS-induced plasticity in health and disease.

The role of neurotransmitters in glioblastoma multiforme-associated seizures

GBM, or glioblastoma multiforme, is a brain tumor that poses a great threat to both children and adults, being the primary cause of death related to brain tumors. GBM is often associated with epilepsy, which can be debilitating. Seizures and the development of epilepsy are the primary symptoms that have a severe impact on the quality of life for GBM patients. It is increasingly apparent that the nervous system plays an essential role in the tumor microenvironment for all cancer types, including GBM. In recent years, there has been a growing understanding of how neurotransmitters control the progression of gliomas. Evidence suggests that neurotransmitters and neuromodulators found in the tumor microenvironment play crucial roles in the excitability, proliferation, quiescence, and differentiation of neurons, glial cells, and neural stem cells. The involvement of neurotransmitters appears to play a significant role in various stages of GBM. In this review, the focus is on presenting updated knowledge and emerging ideas regarding the interplay between neurotransmitters and neuromodulators, such as glutamate, GABA, norepinephrine, dopamine, serotonin, adenosine, and their relationship with GBM and the seizures induced by this condition. The review aims to explore the current understanding and provide new insights into the complex interactions between these neurotransmitters and neuromodulators in the context of GBM-related seizures.

Analysis of Adverse Drug Reactions in Pediatric Patients with Epilepsy: An Intensive Pharmacovigilance Study

Epilepsy is a chronic neurological disease characterized by the presence of spontaneous seizures, with a higher incidence in the pediatric population. Anti-seizure medication (ASM) may produce adverse drug reactions (ADRs) with an elevated frequency and a high severity. Thus, the objective of the present study was to analyze, through intensive pharmacovigilance over 112 months, the ADRs produced by valproic acid (VPA), oxcarbazepine (OXC), phenytoin (PHT), and levetiracetam (LEV), among others, administered to monotherapy or polytherapy for Mexican hospitalized pediatric epilepsy patients. A total of 1034 patients were interviewed; 315 met the inclusion criteria, 211 patients presented ADRs, and 104 did not. A total of 548 ASM-ADRs were identified, and VPA, LEV, and PHT were the main culprit drugs. The most frequent ADRs were drowsiness, irritability, and thrombocytopenia, and the main systems affected were hematologic, nervous, and dermatologic. LEV and OXC caused more nonsevere ADRs, and PHT caused more severe ADRs. The risk analysis showed an association between belonging to the younger groups and polytherapy with ADR presence and between polytherapy and malnutrition with severe ADRs. In addition, most of the severe ADRs were preventable, and most of the nonsevere ADRs were nonpreventable.

Caffeine impairs anticonvulsant effects of levetiracetam in the maximal electroshock seizure threshold test in mice

OBJECTIVES

Caffeine is the most widely used psychoactive substance in the world. Animal studies indicate that acute caffeine exposure at high doses may induce seizures and diminish the anticonvulsant activity of antiepileptic drugs (AEDs) at much lower doses. The aim of the current study was to assess the effect of caffeine on the anticonvulsant action of levetiracetam (LEV) and vigabatrin (VGB).

METHODS

The anticonvulsant activity of LEV and VGB was examined in the maximal electroshock seizure threshold test in mice (MEST test). All drugs were administered intraperitoneally by single injections, and caffeine was applied at doses capable of interfering with AEDs. Effects of caffeine exposure on AEDs were also investigated in tests of memory and motor performance.

RESULTS

Caffeine reduced the protective effect of LEV against electroconvulsions. Total brain concentration of LEV was unaffected by caffeine as well as inversely; LEV had no significant impact on the brain caffeine concentration, suggesting a pharmacodynamic nature of the interaction between LEV and caffeine in the MEST test. VGB at applied doses did not affect the convulsive threshold. Administration of VGB, but not LEV, alone or in combination with caffeine, impaired memory retention. In the chimney test, the combined treatment with AEDs and caffeine did not cause motor coordination impairment.

CONCLUSIONS

It is suggested that caffeine may negatively affect the anticonvulsant action of LEV in patients with epilepsy.

Levetiracetam, from broad-spectrum use to precision prescription: A narrative review and expert opinion

Levetiracetam (LEV) is an antiseizure medication (ASM) whose mechanism of action involves the modulation of neurotransmitters release through binding to the synaptic vesicle glycoprotein 2A. It is a broad-spectrum ASM displaying favorable pharmacokinetic and tolerability profiles. Since its introduction in 1999, it has been widely prescribed, becoming the first-line treatment for numerous epilepsy syndromes and clinical scenarios. However, this might have resulted in overuse. Increasing evidence, including the recently published SANAD II trials, suggests that other ASMs are reasonable therapeutic options for generalized and focal epilepsies. Not infrequently, these ASMs show better safety and effectiveness profiles compared to LEV (partially due to the latter's well-known cognitive and behavioral adverse effects, present in up to 20% of patients). Moreover, it has been shown that the underlying etiology of epilepsy is significantly linked to ASMs response in particular scenarios, highlighting the importance of an etiology-based ASM choice. In the case of LEV, it has demonstrated an optimal effectiveness in Alzheimer's disease, Down syndrome, and PCDH19-related epilepsies whereas, in other etiologies such as malformations of cortical development, it may show negligible effects. This narrative review analyzes the current evidence related to the use of LEV for the treatment of seizures. Illustrative clinical scenarios and practical decision-making approaches are also addressed, therefore aiming to define a rational use of this ASM.

Antitumor Potential of Antiepileptic Drugs in Human Glioblastoma: Pharmacological Targets and Clinical Benefits

Glioblastoma (GBM) is characterized by fast-growing cells, genetic and phenotypic heterogeneity, and radio-chemo-therapy resistance, contributing to its dismal prognosis. Various medical comorbidities are associated with the natural history of GBM. The most disabling and greatly affecting patients' quality of life are neurodegeneration, cognitive impairment, and GBM-related epilepsy (GRE). Hallmarks of GBM include molecular intrinsic mediators and pathways, but emerging evidence supports the key role of non-malignant cells within the tumor microenvironment in GBM aggressive behavior. In this context, hyper-excitability of neurons, mediated by glutamatergic and GABAergic imbalance, contributing to GBM growth strengthens the cancer-nervous system crosstalk. Pathogenic mechanisms, clinical features, and pharmacological management of GRE with antiepileptic drugs (AEDs) and their interactions are poorly explored, yet it is a potentially promising field of research in cancer neuroscience. The present review summarizes emerging cooperative mechanisms in oncogenesis and epileptogenesis, focusing on the neuron-to-glioma interface. The main effects and efficacy of selected AEDs used in the management of GRE are discussed in this paper, as well as their potential beneficial activity as antitumor treatment. Overall, although still many unclear processes overlapping in GBM growth and seizure onset need to be elucidated, this review focuses on the intriguing targeting of GBM-neuron mutual interactions to improve the outcome of the so challenging to treat GBM.

Perinatal hypoxia and thalamus brain region: increased efficiency of antiepileptic drug levetiracetam to inhibit GABA release from nerve terminals

Levetiracetam (LV), 2S-(2-oxo-1-pyrrolidiny1) butanamide, is an antiepileptic drug. The exact mechanisms of anticonvulsant effects of LV remain unclear. In this study, rats (Wistar strain) underwent hypoxia and seizures at the age of 10–12 postnatal days (pd). [3H]GABA release was analysed in isolated from thalamus nerve terminals (synaptosomes) during development at the age of pd 17–19 and pd 24–26 (infantile stage), pd 38–40 (puberty) and pd 66–73 (young adults) in control and after perinatal hypoxia. The extracellular level of [3H]GABA in the preparation of thalamic synaptosomes increased during development at the age of pd 38–40 and pd 66–73 as compared to earlier ones. LV did not influence the extracellular level of [3H]GABA in control and after perinatal hypoxia at all studied ages. Exocytotic [3H]GABA release in control increased at the age of pd 24–26 as compared to pd 17–19. After hypoxia, exocytotic [3H]GABA release from synaptosomes also increased during development. LV elevated [3H]GABA release from thalamic synaptosomes at the age of pd 66–73 after hypoxia and during blockage of GABA uptake by NO-711 only. LV realizes its antiepileptic effects at the presynaptic site through an increase in exocytotic release of [3H]GABA in thalamic synaptosomes after perinatal hypoxia at pd 66–73. LV exhibited a more significant effect in thalamic synaptosomes after perinatal hypoxia than in control ones. The action of LV is age-dependent, and the drug was inert at the infantile stage that can be useful for an LV application strategy in child epilepsy therapy. Keywords: brain development, exocytosis, GABA, levetiracetam, perinatal hypoxia, thalamic synaptosomes

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.

Levetiracetam or Phenobarbitone as a First-Line Anticonvulsant in Asphyxiated Term Newborns? An Open-Label, Single-Center, Randomized, Controlled, Pragmatic Trial

BACKGROUND AND OBJECTIVE

Neonatal seizures are one of the most challenging problems for experts across the globe. Although there is no consensus on the "ideal" treatment of neonatal seizures, phenobarbitone has been the drug of choice for decades. Unfortunately, although extensively studied in adults and children, levetiracetam lacks rigorous evaluation in the neonatal population, despite its frequent use as an off-label drug. The objective of this open-label, randomized, active-control, single-center, pragmatic trial was to compare the effectiveness of levetiracetam with phenobarbitone for term asphyxiated infants as a first-line drug.

METHODS

The participants included in this study were inborn term asphyxiated infants with seizures in the first 48 hours of life. Infants satisfying the inclusion criteria were randomized to receive levetiracetam (20 mg/kg) or phenobarbitone (20 mg/kg). Clinical seizure control was noted. Infants who failed to respond to the primary drug were given the other group drug.

RESULTS

Of 103 eligible infants, 82 were randomly assigned (44 levetiracetam group, 38 phenobarbitone group). Clinical seizure control with the primary drug and maintenance of the same for 24 hours was observed in 29 infants (65.9%) in the levetiracetam group and 13 infants (34.2%) in the phenobarbitone group (P < .05, relative risk 0.52, 95% confidence interval 0.32-0.84). Of the infants in the phenobarbitone group who did not respond to the primary drug, 57.8% were controlled after adding levetiracetam.

CONCLUSION

Levetiracetam can be used with effectiveness as a first- and second-line drug in asphyxiated term infants. A more extensive study on pharmacokinetics and optimal regimen is required.

Levetiracetam Mechanisms of Action: From Molecules to Systems

Epilepsy is a chronic disease that affects millions of people worldwide. Antiepileptic drugs (AEDs) are used to control seizures. Even though parts of their mechanisms of action are known, there are still components that need to be studied. Therefore, the search for novel drugs, new molecular targets, and a better understanding of the mechanisms of action of existing drugs is still crucial. Levetiracetam (LEV) is an AED that has been shown to be effective in seizure control and is well-tolerable, with a novel mechanism of action through an interaction with the synaptic vesicle protein 2A (SV2A). Moreover, LEV has other molecular targets that involve calcium homeostasis, the GABAergic system, and AMPA receptors among others, that might be integrated into a single mechanism of action that could explain the antiepileptogenic, anti-inflammatory, neuroprotective, and antioxidant properties of LEV. This puts it as a possible multitarget drug with clinical applications other than for epilepsy. According to the above, the objective of this work was to carry out a comprehensive and integrative review of LEV in relation to its clinical uses, structural properties, therapeutical targets, and different molecular, genetic, and systemic action mechanisms in order to consider LEV as a candidate for drug repurposing.

Pain in Multiple Sclerosis: Understanding Pathophysiology, Diagnosis, and Management Through Clinical Vignettes

Neuropathic pain and other pain syndromes occur in the vast majority of patients with multiple sclerosis at some time during their disease course. Pain can become chronic and paroxysmal. In this review, we will utilize clinical vignettes to describe various pain syndromes associated with multiple sclerosis and their pathophysiology. These syndromes vary from central neuropathic pain or Lhermitte's phenomenon associated with central nervous system lesions to trigeminal neuralgia and optic neuritis pain associated with nerve lesions. Muscular pain can also arise due to spasticity. In addition, we will discuss strategies utilized to help patients manage these symptoms.

Adverse effects of antiepileptic drugs on hormones of the hypothalamic-pituitary-gonadal axis in males: A review

The HPG axis is critical in the maintenance of spermatogenesis and sexual function in males. The GnRH-releasing neurons of the hypothalamus are the axis's main hierarchical element. These neurons make connections with different areas of the brain to regulate the release of GnRH. Neurotransmitters have a critical in the connections between these neurons. So, neurotransmitters can inhibit or stimulate the release of GnRH by affecting GnRH-releasing neurons. In neurological disorders, neurotransmitter's activities inevitably change; therefore, these changes can affect the HPG axis via affecting GnRH-releasing neurons, just like in epilepsy. Many investigations have attracted attention to be decreased fertility potential in males with epilepsy. It has been stated that changes in the HPG axis hormone levels have been found in these patients. Moreover, it has also been observed that sperm quality decreased in patients. It has been emphasized that a decrease in sperm quality may be related to both epilepsy and AEDs. It has been shown that AEDs caused decreased sperm quality by impairing the HPG axis, so they act like endocrine-disrupting chemicals. AEDs can affect fertility and cause additive adverse effects in terms of sperm quality together with epilepsy. Therefore, it is crucial to investigate the adverse reproductive effects of AEDs, which are frequently used during reproductive ages, and determine the role of the HPG axis on potential reproductive pathologies.

Modulation of nociception and pain-evoked neurobehavioral responses by levetiracetam in a craniotomy pain model

Traditional and novel analgesic modalities have been extensively tested for post-craniotomy pain management, yet the role of newer antiepileptic drugs in this area remains obscure. This study investigates the impact of levetiracetam (LEV) on pain modulation and neurobehavioral performance in a craniotomy model. Fifty-six Wistar rats were randomly assigned into seven groups: no intervention (CTRL), administration of placebo or LEV with no further intervention (PBO and LEV, respectively), and sham-operation or craniotomy in placebo (PBO-SHAM and PBO-CR, respectively) or LEV-treated rats (LEV-SHAM and LEV-CR, respectively). Pain was assessed by the rat grimace scale before, and at 8 and 24 h after craniotomy, following intraperitoneal injections of LEV (100 mg/kg twice daily) or normal saline two consecutive days before and on the craniotomy day. Elevated plus-maze and olfactory social memory tests were performed at 24- and 48 h post-craniotomy, respectively. Upon testing conclusion blood samples were collected for cytokines estimation. Levetiracetam administration enhanced antinociception in sham and craniotomy groups. In the elevated plus-maze test, LEV-CR rats spent more time in investigating open arms and performed more open arm entries than PBO-SHAM and PBO-CR animals. The olfactory test revealed no between-groups difference in acquisition time during first contact with a juvenile rat, while LEV-CR rats spent less time to recognize the same juvenile rat compared to PBO-SHAM and PBO-CR groups. Furthermore, LEV-treatment attenuated cortisol, interleukin-6 and TNF-a release, in sham and craniotomy animals. In conclusion, preemptive use of LEV decreases nociception, improves pain-evoked behavior and attenuates stress response in rats subjected to craniotomy.

Therapeutic Options for Childhood Absence Epilepsy

Childhood absence epilepsy (CAE) is a common pediatric generalized epileptic syndrome. Although it is traditionally considered as a benign self-limited condition, the apparent benign nature of this syndrome has been revaluated in recent years. This is mainly due to the increasing evidence that children with CAE can present invalidating neuropsychological comorbidities that will affect them up to adulthood. Moreover, a percentage of affected children can develop drug-resistant forms of CAE. The purpose of this review is to summarize the most recent studies and new concepts concerning CAE treatment, in particular concerning drug-resistant forms of CAE. A Pubmed search was undertaken to identify all articles concerning management and treatment of CAE, including articles written between 1979 and 2021. Traditional anticonvulsant therapy of CAE that is still in use is based on three antiepileptic drugs: ethosuximide which is the drug of choice, followed by valproic acid and lamotrigine. In the case of first line treatment failure, after two monotherapies it is usual to start a bi-therapy. In the case of absence seizures that are refractory to traditional treatment, other antiepileptic drugs may be introduced such as levetiracetam, topiramate and zonisamide.

Relevant pharmacological interactions between alkylating agents and antiepileptic drugs: Preclinical and clinical data

Seizures are relatively common in cancer patients, and co-administration of chemotherapeutic and antiepileptic drugs (AEDs) is highly probable and necessary in many cases. Nonetheless, clinically relevant interactions between chemotherapeutic drugs and AEDs are rarely summarized and pharmacologically described. These interactions can cause insufficient tumor and seizure control or lead to unforeseen toxicity. This review focused on pharmacokinetic and pharmacodynamic interactions between alkylating agents and AEDs, helping readers to make a rational choice of treatment optimization, and thus improving patients' quality of life. As an example, phenobarbital, phenytoin, and carbamazepine, by increasing the hepatic metabolism of cyclophosphamide, ifosfamide and busulfan, yield smaller peak concentrations and a reduced area under the plasma concentration-time curve (AUC) of the prodrugs; alongside, the maximum concentration and AUC of their active products were increased with the possible onset of severe adverse drug reactions. On the other side, valproic acid, acting as histone deacetylase inhibitor, showed synergistic effects with temozolomide when tested in glioblastoma. The present review is aimed at providing evidence that may offer useful suggestions for rational pharmacological strategies in patients with seizures symptoms undertaking alkylating agents. Firstly, clinicians should avoid the use of enzyme-inducing AEDs in combination with alkylating agents and prefer the use of AEDs, such as levetiracetam, that have a low or no impact on hepatic metabolism. Secondly, a careful therapeutic drug monitoring of both alkylating agents and AEDs (and their active metabolites) is necessary to maintain therapeutic ranges and to avoid serious adverse reactions.

Effect of Levetiracetam Use Duration on Overall Survival of Isocitrate Dehydrogenase Wildtype Glioblastoma in Adults: An Observational Study

OBJECTIVES

The association between Levetiracetam and survival of Isocitrate Dehydrogenase (IDH) wildtype glioblastomas is controversial. We investigated whether the duration of Levetiracetam use during the standard chemoradiation protocol impacts overall survival of IDH-wildtype glioblastoma patients.

METHODS

Observational single-institution cohort study (2010-2018). Inclusion criteria were: 1) patients ≥18 years old; 2) newly diagnosed supratentorial tumor; 3) histomolecular diagnosis of IDH-wildtype glioblastoma; 4) standard chemoradiation protocol. To assess the survival benefit of Levetiracetam use during the standard chemoradiation protocol (whole duration, part time, and never subgroups), a Cox proportional hazard model was constructed. We performed a case-matched analysis (1:1) between patients with Levetiracetam use during the whole duration of the standard chemoradiation protocol and patients with Levetiracetam use part time or never according to the following criteria: sex, age, epileptic seizures at diagnosis, RTOG-RPA class, tumor location, preoperative volume, extent of resection, and O6-Methylguanine-DNA methyltransferase promoter methylation status. Patients with unavailable O6-Methylguanine-DNA methyltransferase promoter methylation status (48.5%) were excluded.

RESULTS

460 patients were included. The median overall survival was longer in the 116 patients with Levetiracetam use during the whole duration of the standard chemoradiation protocol (21.0 months; 95%CI, 17.2-24.0) than in the 126 patients with part time Levetiracetam use (16.8 months; 95%CI, 12.4-19.0], and in the 218 patients who never received Levetiracetam (16.0 months; 95%CI, 15.5-19.4; p=0.027). Levetiracetam use during the whole duration of the standard chemoradiation protocol (adjusted Hazard Ratio (aHR) 0.69; 95%CI, 0.52-0.93; p=0.014), O6-Methylguanine-DNA methyltransferase promoter methylation (aHR 0.53; 95%CI, 0.39-0.71; p<0.001), and gross total tumor resection (aHR 0.57; 95%CI, 0.44-0.74; p<0.001) were independent predictors of a longer overall survival. After case matching (n=54 per group), a longer overall survival was found for Levetiracetam use during the whole duration of the standard chemoradiation protocol (HR=0.63; 95%CI, 0.42-0.94, p=0.023).

DISCUSSION

Levetiracetam use during the whole standard chemoradiation protocol possibly improves overall survival of IDH-wildtype glioblastoma patients. It should be considered in the anti-tumor strategy of future multicentric trials.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in individuals with IDH-wildtype glioblastoma, levetiracetam use throughout the duration of standard chemotherapy is associated with longer median overall survival.

Effects of new antiseizure drugs on seizure activity and anxiety-like behavior in adult zebrafish

Several studies with larvae and adult zebrafish have shown that old and new antiseizure drugs (ASDs) produce discrepant results in seizure tests, locomotor activity or anxiety models. In this study, the pentylenetetrazole seizure test (PTZ) was performed to assess the effectiveness of four new ASDs: lamotrigine (LTG), topiramate (TPM), felbamate (FBM), and levetiracetam (LEV) in the subsequent stages of seizures in adult fish. All ASDs were administered intraperitoneally (i.p.). The time of maximal anticonvulsant effect and the dose-response relationship of the drugs were assessed. The effects of studied ASDs on the locomotor activity and the anxiety-like behavior in the color preference test were also investigated. Furthermore, drug concentrations in zebrafish homogenates were determined. LTG, TPM, and LEV significantly increased the seizure latency at three subsequent stages of seizures (SI-SIII), while FBM was effective only at SI. Locomotor activity decreased after TPM treatment. TPM and FBM exhibited a strong anxiolytic-like effect in the color preference test. LEV at the highest dose tested had a weak anxiolytic-like effect. The HPLC analysis showed average concentrations of the studied ASDs in the fish body during their maximum anticonvulsant activity. The present study shows that FBM cannot inhibit all subsequent PTZ seizure stages in the adult fish. Except for LTG, the studied drugs affected the anxiety-like behavior of treated animals. Furthermore, only TPM significantly changed locomotion parameters. Our findings support the need to accurately characterize the efficacy of new ASDs at different stages of the PTZ-induced seizures in adult zebrafish.

Safety considerations selecting antiseizure medications for the treatment of individuals with Dravet syndrome

Introduction: Management of individuals with Dravet Syndrome has evolved significantly over the past 10 years. Progress has been made in understanding the pathophysiology, the long-term outcome and possible consequences of inappropriate therapies, new drugs have been approved by the regulatory authorities and patients and families expressed their needs beyond seizures' control.Areas covered: The authors aimed at providing an overview of the main antiseizure medications used in Dravet syndrome with a particular focus on safety considerations. As the highly active phase of seizures takes place before the age of 5 years, the characteristics of antiseizure medications in infancy and childhood have also been considered due to their impact on antiseizure medication safety.Expert opinion: Recent treatments, evaluated via randomized clinical trials, are promising in terms of efficacy and safety in individuals with DS. However, the balance between expected benefits and risks taken must be accurately assessed on an individual basis. There is a lack of data to understand the needs of patients and families, a major point particularly in this population, where the evaluation of efficacy and safety beyond seizures is difficult due to cognitive delay and behavioral disorders and where this evaluation is coming almost exclusively from caregivers.

The effect of complicated febrile convulsion on hippocampal function and its antiepileptic treatment significance

BACKGROUND

This study aimed to explore the effects of complex febrile seizures on hippocampal function and the significance of antiepileptic therapy.

METHODS

A total of 150 children with complex febrile seizures admitted to our hospital from July 2017 to July 2020 were included in the study. The VPA group was given sodium valproate treatment; the LEV group was given levetiracetam treatment; and the observation group was given basic treatment. The efficacy of the patients was evaluated after medication. A complex febrile seizure young mouse model was constructed, and the hippocampal cell morphology and BCL-2 expression of the mice pups were analyzed. A Morris water maze was used to detect the changes in cognitive function of the young mice with complex febrile seizures.

RESULTS

After treatment, the recurrence-free rate of the VPA group was significantly higher than that of the observation group (P=0.0045). After 1 month and 6 months, the improvement rate of EEG in VPA group was significantly higher than that in observation group (P<0.05). After treatment, the levels of BCL-2 in the VPA group and the LEV group decreased and were significantly lower than the observation group during the same period (P<0.05), and the M/C of the two groups was significantly higher than the observation group (P<0.05). The neuronal cells in the hippocampus of the young rats in the VPA group and the LEV group were regular, the matrix was more uniform, and nuclear pyknotic cells were occasionally seen. The pathological changes were less obvious than the model group, followed by the degree of pathological changes (0.92±1.31, 0.94±1.24). The incubation period of pups in the model group was significantly higher than that of the normal group, VPA group, and LEV group (P<0.05), and the number of crossing the station area was significantly less than that of the normal group, VPA group, and LEV group (P<0.05).

CONCLUSIONS

Antiepileptic drugs are effective in preventing the recurrence of complicated febrile seizures (CFS), and the main mechanism may be related to the targeted regulation of BCL-2 on the apoptosis of the hippocampus in the nervous system.

Levetiracetam effect on behavioral and electrophysiological parameters in rat model of global brain ischemia

Post-stroke paroxysmal activity is a neurophysiological indicator of epileptogenesis and increase of seizure susceptibility, so treatments with neuroprotective activity and anti-paroxysmal activity can be more beneficial during post-ischemic period. The goal of this study was evaluation of levetiracetam (100 mg/kg, 7 days of administration) effect on behavior and brain bioelectric activity changes in the post-ischemic period. Global ischemia model was carried out with bilateral ligation of carotid arteries in rats. Neurological deficit and electrophysiological changes of brain structures (striatum, cortex, hypothalamus, hippocampus) were analyzed during 28 days. Paroxysmal activity was not observed on the 1st day after ischemia and had early (2nd day) and late (28th day) onsets. Spectral analysis showed that rats, that died by the 10th day, had delta wave increase and theta decrease on the 1st day and delta activity reduction on the 2-7th days. LEV did not affect survival rate, however, it contributed to neurological disorder regression towards lighter forms on the 1st day after ischemia. It suppressed paroxysmal activity with an early onset and affected delta and theta waves on the 1st day in all structures except hippocampus. On the 7th and 28th days LEV increased delta activity due to 1-3 Hz frequency. Thus, LEV eliminates early onset post-ischemic paroxysmal activity and contributes to normalization of delta waves activity on the 1st day after ischemia, that positively affects neurological status of animals in post-ischemic period. It allows one to make a conclusion about possible LEV application in the post-ischemic period.

Safety and Efficacy of Levetiracetam for the Management of Levodopa- Induced Dyskinesia in Patients with Parkinson's Disease: A Systematic Review

BACKGROUND

Levetiracetam, a novel antiepileptic drug, has shown antidyskinetic effects in experimental animal models of Parkinson's disease (PD). The tolerability and efficacy of levetiracetam in reducing the levodopa-induced dyskinesia (LID) in PD patients have not been established. Therefore, this study aims to synthesize evidence from published prospective clinical trials about the efficacy of levetiracetam for the management of LID in PD patients.

METHODS

We followed the PRISMA statement guidelines during the preparation of this systematic review. A computer literature search of PubMed, EBSCO, Scopus, MEDLINE, and the web of science was carried out. We selected prospective clinical trials assessing the anti-dyskinetic efficacy of levetiracetam for treating LID in patients with PD. The Abnormal Involuntary Movement Scale (AIMS), Clinical Global Impression Score (GCI), UPDRS III, and UPDRS IV were considered as the primary outcome measures; their data were extracted and reviewed.

RESULTS

Our review included seven clinical trials with a total of 150 patients. Of them, three studies were randomized controlled trials, and the remaining were open-label single arm trials. Four studies reported poor tolerability of the levetiracetam with mild anti-dyskinetic effects. Levetiracetam slightly improved the UPDRS-IV and AIMS scores with small effect size. In the remaining three studies, levetiracetam failed to exhibit any anti-dyskinetic effects.

CONCLUSION

Current evidence does not support the efficacy of the levetiracetam for treating LID in PD patients, however, due to the limited number of published randomized control trials (RCTs), further RCTs are required.

Levetiracetam add-on for drug-resistant focal epilepsy

BACKGROUND

Drug resistance is common in focal epilepsy. In this update, we summarised the current evidence regarding add-on levetiracetam in treating drug-resistant focal epilepsy. The original review was published in 2001 and last updated in 2012.

OBJECTIVES

To evaluate the effectiveness of levetiracetam when used as an add-on treatment for people with drug-resistant focal epilepsy.

SEARCH METHODS

We searched the Cochrane Register of Studies (CRS Web, which includes the Cochrane Epilepsy Group Specialized Register and CENTRAL), MEDLINE Ovid, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) to November 2018. We contacted the manufacturers of levetiracetam and researchers in the field to seek any ongoing or unpublished trials.

SELECTION CRITERIA

Randomised, placebo-controlled trials of add-on levetiracetam treatment in people with drug-resistant focal epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trials for bias, extracted data, and evaluated the overall certainty of the evidence. Outcomes investigated included 50% or greater reduction in focal seizure frequency (response), treatment withdrawal, adverse effects (including a specific analysis of changes in behaviour), cognitive effects, and quality of life (QoL). Primary analysis was intention-to-treat. We performed meta-analysis for all outcomes using a Mantel-Haenszel approach and calculated risk ratios (RR), with 95% confidence intervals (CI) for all estimates apart from adverse effects (99% CIs). We assessed heterogeneity using a Chi² test and the I² statistic.

MAIN RESULTS

This update included 14 trials (2455 participants), predominantly possessing low risks of bias. Participants were adults in 12 trials (2159 participants) and children in the remaining two (296 participants). The doses of levetiracetam tested were 500 mg/day to 4000 mg/day in adults, and 60 mg/kg/day in children. Treatment ranged from 12 to 24 weeks. When individual doses were examined, levetiracetam at either 500 mg/day or 4000 mg/day did not perform better than placebo for the 50% or greater reduction in seizure frequency outcome (500 mg: RR 1.60, 95% CI 0.71 to 3.62; P = 0.26; 4000 mg: RR 1.64, 95% CI 0.59 to 4.57; P = 0.34). Levetiracetam was significantly better than placebo at all other individual doses (1000 mg to 3000 mg). RR was significantly in favour of levetiracetam compared to placebo when results were pooled across all doses (RR 2.37, 95% CI 2.02 to 2.78; 14 studies, 2455 participants; moderate-certainty evidence). Dose-response analysis demonstrated that the odds of achieving response (50% or greater reduction in seizure frequency) were increased by nearly 40% (odds ratio (OR) 1.39, 95% CI 1.23 to 1.58) for each 1000 mg increase in dose of levetiracetam. There were important levels of heterogeneity across multiple comparisons. Participants were not significantly more likely to experience treatment withdrawal with levetiracetam than with placebo (pooled RR 1.11, 95% CI 0.89 to 1.40; 13 studies, 2428 participants; high-certainty evidence). Somnolence was the most common adverse effect, affecting 13% of participants, and it was significantly associated with levetiracetam compared to placebo (pooled RR 1.62, 99% CI 1.19 to 2.20; 13 studies, 2423 participants; moderate-certainty evidence). Changes in behaviour were negligible in adults (1% affected; RR 1.79, 99% CI 0.59 to 5.41), but significant in children (23% affected; RR 1.90, 99% CI 1.16 to 3.11). Levetiracetam had a positive effect on some aspects of cognition and QoL in adults and worsened certain aspects of child behaviour.

AUTHORS' CONCLUSIONS

Overall, this review update finds that in both adults and children with drug-resistant focal epilepsy, levetiracetam added on to usual care is more effective than placebo at reducing seizure frequency, it is unlikely to be stopped by patients, and it has minimal adverse effects outside of potential worsening behaviour in children. These findings are unchanged from the previous review update in 2012. This review update contributes two key additional findings: 1. a 500 mg daily dose of levetiracetam is no more effective than placebo at reducing seizures; and 2. the odds of response (50% reduction in seizure frequency) are increased by nearly 40% for each 1000 mg increase in dose of levetiracetam. It seems reasonable to continue the use of levetiracetam in both adults and children with drug-resistant focal epilepsy.

Levetiracetam induction of theta frequency oscillations in rodent hippocampus in vitro

Levetiracetam (LEV) has been demonstrated to improve cognitive function. Hippocampal theta rhythm (4-12 Hz) is associated with a variety of cognitively related behaviors, such as exploration in both humans and animal models. We investigated the effects of LEV on the theta rhythm in the rat hippocampal CA3 in hippocampal slices in vitro. We found that LEV increased the theta power in a dose-dependent manner. The increase in theta power can be blocked by GABA_A receptor (GABA_AR) or NMDA receptor (NMDAR) antagonists but not by AMPA receptor antagonist, indicating the involvement of GABA_AR and NMDAR in the induction of theta activity. Interestingly, LEV enhancement of theta power can be also blocked by taurine or GABA-A agonist THIP, indicating that LEV induction of theta may be related to the indirect boosting of GABA action via reduction of extrasynaptic GABA_AR activation. Furthermore, the increased theta power can be partially reduced by the mACh receptor (mAChR) antagonist atropine but not by nACh receptor antagonists, suggesting that mAChR activation provides excitatory input into local network responsible for LEV-induced theta. Our study demonstrated that LEV induced a novel theta oscillation in vitro, which may have implications in the treatment of the neuronal disorders with impaired theta oscillation and cognitive function.

Effect of levetiracetam drug on antioxidant and liver enzymes in epileptic patients: case-control study

BACKGROUND

There is a limited amount of data regarding levetiracetam (LEV), an antiepileptic drug.

OBJECTIVE

This study was conducted to assess the effect of LEV on antioxidant status and liver enzymes.

METHODS

In this case-control study, 33 epileptic patients under treatment with LEV for at least 6 months were compared with 35 healthy subjects. We measured serum total antioxidant capacity (TAC), salivary superoxide dismutase (SOD), alanine aminoteransferase (ALT), and aspartate aminoteransferase (AST) levels in both groups. Dietary intakes were collected using a Food Frequency Questionnaire (FFQ).

RESULT

The level of TAC in the healthy subjects was significantly higher than it was in the patients (P=0.02), but the mean of ALT (P=0.02) and AST (P=0.03) was significantly higher in the patients in comparison with the controls. Mean salivary SOD showed no difference between the two groups. In the patients, the duration of drug use was inversely correlated with serum TAC (p=0.04) and had a direct correlation with ALT (p=0.01) and AST (p=0.03.).

CONCLUSION

The results of our study indicated that LEV increased liver enzymes Also, treatment with this drug did not improve oxidative stress, but this could be due to the different in the dietary antioxidant intake. Routine screening of the liver and antioxidant enzymes in patients with chronic use of LEV is recommended.

Efficacy, Safety, and Economics of Intravenous Levetiracetam for Status Epilepticus: A Systematic Review and Meta-Analysis

Objective

To evaluate efficacy, safety, and economics profiles of intravenous levetiracetam (LEV) for status epilepticus (SE).

Methods

We searched PubMed, Embase, the Cochrane Library, Clinicaltrials.gov, and OpenGrey.eu for eligible studies published from inception to June 12^th 2019. Meta-analyses were conducted using random-effect model to calculate odds ratio (OR) of included randomized controlled trials (RCTs) with RevMan 5.3 software.

Results

A total of 478 studies were obtained. Five systematic reviews (SRs)/meta-analyses, 9 RCTs, 1 non-randomized trial, and 27 case series/reports and 1 economic study met the inclusion criteria. Five SRs indicated no statistically significant difference in rates of seizure cessation when LEV was compared with lorazepam (LOR), phenytoin (PHT), or valproate (VPA). Pooled results of included RCTs indicated no statistically significant difference in seizure cessation when LEV was compared with LOR [OR = 1.04, 95% confidence interval (CI) 0.37 to 2.92], PHT (OR = 0.90, 95% CI 0.64 to 1.27), and VPA (OR = 1.47, 95% CI 0.81 to 2.67); and no statistically significant difference in seizure freedom within 24 h compared with LOR [OR = 1.83, 95% CI 0.57 to 5.90] and PHT (OR = 1.08, 95% CI 0.63 to 1.87). Meanwhile, LEV did not increase the risk of mortality during hospitalization compared with LOR (OR = 1.03, 95% CI 0.31 to 3.39), PHT (OR = 0.89, 95% CI 0.37 to 2.10), VPA (OR = 1.28, 95% CI 0.32 to 5.07), and placebo (plus clonazepam, OR = 0.73, 95% CI 0.16 to 3.38). LEV had lower need for artificial ventilation (OR = 0.23, 95% CI 0.06 to 0.92) and a lower risk of hypotension (OR = 0.15, 95% CI 0.03 to 0.84) compared to LOR. A trend of lower risk of hypotension and higher risk of agitation was found when LEV was compared with PHT. Case series and case report studies indicated psychiatric and behavioral adverse events of LEV. Cost-effectiveness evaluations indicated LEV as the most cost-effective non-benzodiazepines anti-epileptic drug (AED).

Conclusions

LEV has a similar efficacy as LOR, PHT, and VPA for SE, but a lower need for ventilator assistance and risk of hypotension, thus can be used as a second-line treatment for SE. However, more well-conducted studies to confirm the role of intravenous LEV for SE are still needed.

The adverse effects of psychotropic drugs as an endocrine disrupting chemicals on the hypothalamic-pituitary regulation in male

Adverse effects of drugs on male reproductive system can be categorized as pre-testicular, testicular, and post-testicular. Pre-testicular adverse effects disrupt the hypothalamic-pituitary-gonadal (HPG) axis, generally by interfering with endocrine function. It is known that the HPG axis has roles in the maintenance of spermatogenesis and sexual function. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which enters the hypophyseal portal system to stimulate the anterior pituitary. The anterior pituitary secretes gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) which are vital for spermatogenesis, into the blood. The FSH stimulates the Sertoli cells for the production of regulatory molecules and nutrients needed for the maintenance of spermatogenesis, while the LH stimulates the Leydig cells to produce and secrete testosterone. Many neurotransmitters influence the hypothalamic-pituitary regulation, consequently the HPG axis, and can consequently affect spermatogenesis and sexual function. Psychotropic drugs including antipsychotics, antidepressants, and mood stabilizers that all commonly modulate dopamine, serotonin, and GABA, can affect male spermatogenesis and sexual function by impairment of the hypothalamic-pituitary regulation, act like endocrine-disrupting chemicals. Otherwise, studies have shown the relationship between decreased sperm quality and psychotropic drugs treatment. Therefore, it is important to investigate the adverse reproductive effects of psychotropic drugs which are frequently used during reproductive ages in males and to determine the role of the hypothalamic-pituitary regulation axis on possible pathologies.

Epileptogenesis and oncogenesis: An antineoplastic role for antiepileptic drugs in brain tumours?

The first description of epileptic seizures due to brain tumours occurred in 19th century. Nevertheless, after over one hundred years, scientific literature is still lacking on how epilepsy and its treatment can affect tumour burden, progression and clinical outcomes. In patients with brain tumours, epilepsy dramatically impacts their quality of life (QoL). Even antiepileptic therapy seems to affect tumor lesion development. Numerous studies suggest that certain actors involved in epileptogenesis (inflammatory changes, glutamate and its ionotropic and metabotropic receptors, GABA-A and its GABA-AR receptor, as well as certain ligand- and voltage-gated ion channel) may also contribute to tumorigenesis. Although some antiepileptic drugs (AEDs) are known operating on such mechanisms underlying epilepsy and tumor development, few preclinical and clinical studies have tried to investigate them as targets of pharmacological tools acting to control both phenomena. The primary aim of this review is to summarize known determinants and pathophysiological mechanisms of seizures, as well as of cell growth and spread, in patients with brain tumors. Therefore, a special focus will be provided on the anticancer effects of commonly prescribed AEDs (including levetiracetam, valproic acid, oxcarbazepine and others), with an overview of both preclinical and clinical data. Potential clinical applications of this finding are discussed.

An interaction study of Ocimum sanctum L. and levetiracetam in pentylenetetrazole kindling model of epilepsy

ETHNOPHARMACOLOGICAL RELEVANCE

Ocimum sanctum L. commonly known as tulsi (synonym of Ocimum tenuiflorum L.) is widely used in Ayurveda medicine and is having multitude neuromodulatory effect including the anticonvulsant effect in acute seizure models as per previous studies. In India, it is used for the treatment of epilepsy as traditional medicine. However, its role in chronic seizure model and interaction with newer antiepileptic drugs has not been investigated, which will enhance its translational value.

AIM OF THE STUDY

Current study investigated the effect of Ocimum on chronic seizure model and its interaction with levetiracetam (LEV), a newer antiepileptic drug.

MATERIALS AND METHODS

The adjuvant role of Ocimum sanctum hydroalcoholic extracts (OSHE) 1000 mg/kg along with LEV 300 mg/kg was studied in adult male Wistar rats with mean weight of 227.84 ± 21.68 g using pentylenetetrazole (30 mg/kg, i.p.) kindling (K) (with maximum 24 injections on alternate days and challenge on 7th-day). Along with seizure score, neurobehavioral, brain tissue oxidative stress and histopathology status were assessed. Pharmacokinetic interaction was assessed between LEV and OSHE after 14 days of drug treatment.

RESULTS

K-LEV + OSHE had least seizure score during kindling and on the pentylenetetrazole-challenge test (p=0.031) than other kindling groups. Seizure protection was more in K-LEV + OSHE (85.72%) than others (K-LEV-42.86%, K-OSHE-42.86%, and K-Control-28.58%). Ocimum treated groups had better memory retention potential as evident from Morris water maze (MWM), passive avoidance test but not in an elevated plus maze test. Oxidative-stress was lower in Ocimum treated groups than K-Control group. As per histopathology, K-LEV + OSHE group had the least neuronal degeneration among kindling groups. There was no significant pharmacokinetic interaction between LEV and OSHE, except increased T_max in LEV + OSHE group than LEV alone (p=0.009).

CONCLUSIONS

Ocimum per se and combination with levetiracetam treatment exerted better seizure control, memory retention, oxidative stress reduction, and neuronal structure preservation than kindling control group. There was a very minimal drug interaction between Ocimum and LEV. So, Ocimum as an adjuvant to LEV may be shelpful in enhancing the antiepileptic effect and also in minimizing the adverse effects.

Mechanisms of action of currently used antiseizure drugs

Antiseizure drugs (ASDs) prevent the occurrence of seizures; there is no evidence that they have disease-modifying properties. In the more than 160 years that orally administered ASDs have been available for epilepsy therapy, most agents entering clinical practice were either discovered serendipitously or with the use of animal seizure models. The ASDs originating from these approaches act on brain excitability mechanisms to interfere with the generation and spread of epileptic hyperexcitability, but they do not address the specific defects that are pathogenic in the epilepsies for which they are prescribed, which in most cases are not well understood. There are four broad classes of such ASD mechanisms: (1) modulation of voltage-gated sodium channels (e.g. phenytoin, carbamazepine, lamotrigine), voltage-gated calcium channels (e.g. ethosuximide), and voltage-gated potassium channels [e.g. retigabine (ezogabine)]; (2) enhancement of GABA-mediated inhibitory neurotransmission (e.g. benzodiazepines, tiagabine, vigabatrin); (3) attenuation of glutamate-mediated excitatory neurotransmission (e.g. perampanel); and (4) modulation of neurotransmitter release via a presynaptic action (e.g. levetiracetam, brivaracetam, gabapentin, pregabalin). In the past two decades there has been great progress in identifying the pathophysiological mechanisms of many genetic epilepsies. Given this new understanding, attempts are being made to engineer specific small molecule, antisense and gene therapies that functionally reverse or structurally correct pathogenic defects in epilepsy syndromes. In the near future, these new therapies will begin a paradigm shift in the treatment of some rare genetic epilepsy syndromes, but targeted therapies will remain elusive for the vast majority of epilepsies until their causes are identified. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Effects of Levetiracetam Compared to Valproate on Cognitive Functions of Patients with Epilepsy

OBJECTIVE

This study compared the effect of levetiracetam (LEV) as monotherapy to sodium valproate (VPA) as monotherapy on cognitive functions in patients with epilepsy.

METHODS

This was a comparative prospective study on 50 patients with newly diagnosed epilepsy started on antiseizure medications. Patients were selected from the neurology-outpatient clinics at Minia University Hospital, Minia, Egypt. They were divided into two groups: group treated with LEV and group treated with VPA. All patients were subjected to cognitive function assessment using reaction-time tests, trail-making tests, and Wisconsin card-sorting test before treatment and 3 months after treatment.

RESULTS

Both groups of patients showed reduction in seizure frequency. However, patients on LEV showed significant improvement in measured cognitive functions 3 months after starting treatment, while patients in the VPA group showed significant impairment in measured cognitive functions 3 months after starting treatment.

CONCLUSION

Both groups of patients showed reduction in seizure frequency. However, patients on LEV showed significant improvement in measured cognitive functions 3 months after starting treatment, while patients in the VPA group showed significant impairment in measured cognitive functions 3 months after starting treatment.

The potential effects of anticonvulsant drugs on neuropeptides and neurotrophins in pentylenetetrazol kindled seizures in the rat

Purpose: Neuropeptides and neurotrophic factors are thought to be involved in epileptogenesis. This study aims to investigate the potential effects of anticonvulsant drugs on neuropeptides (galanin and neuropeptide Y) and neurotrophic factors (BDNF and NGF) in pentylenetetrazol (PTZ)-kindled seizures in the rat.Methods: Forty-eight adult male Sprague-Dawley rats were included in the study. The animals were divided into 8 groups of six rats. Group 1 was defined as naïve control, and received no medication. Group 2 (PTZ + saline) was treated with sub-convulsive doses of PTZ (35 mg/kg) and saline i.p. for 14 days. For anticonvulsant treatments, Groups 3-8 were treated with 200 mg/kg levetiracetam (PTZ + LEV), 1 mg/kg midazolam (PTZ + MDZ), 80 mg/kg phenytoin (PTZ + PHT), 80 mg/kg topiramate (PTZ + TPR), 40 mg/kg lamotrigine (PTZ + LMT) and 50 mg/kg sodium valproate (PTZ + SV), respectively. All anticonvulsant drugs were injected 30 min prior to PTZ injection throughout 14 days. Following treatment period, behavioral, biochemical and immunohistochemical studies were performed.Results: PTZ + saline group revealed significantly decreased galanin, NPY, BDNF and NGF levels compared to control. PTZ + MDZ group had significantly increased galanin, BDNF and NGF levels compared to saline group. Also, PTZ + LEV group showed increased BDNF levels. PTZ + saline group revealed significantly lower neuron count and higher GFAP (+) cells in hippocampal CA1-CA3 regions. All anticonvulsants significantly reduced hippocampal astrogliosis whereas only midazolam, levetiracetam, sodium valproate and lamotrigine prevented neuronal loss.Conclusion: Our results suggested that anticonvulsant drugs may reduce the severity of seizures, and exert neuroprotective effects by altering the expression of neuropeptides and neurotrophins in the epileptogenic hippocampus.

Levetiracetam effect and electrophysiological mechanism of action in rats with cobalt-induced chronic epilepsy

Levetiracetam was initially developed as a nootropic drug, although since 2002 it has been used as anticonvulsant for the treatment of partial and generalized epilepsy syndromes. The purpose of the research was to investigate anti-paroxysmal activity of levetiracetam (LEV) on the model of cobalt-induced chronic epilepsy caused by the application of cobalt to the sensorimotor area of the rat cortex to evaluate LEV impact on the different stages of epileptogenesis. LEV effects were studied at the initial stage of the epileptogenesis (2nd day after the cobalt application) and at the stage of generalized paroxysmal activity (6th day after the cobalt application). The research showed that levetiracetam administration (dosages 50 mg/kg and 200 mg/kg) at the early stage of the epileptogenesis had no statistically significant effect on the development of paroxysmal activity in both primary and secondary epileptic areas: in the ipsi- and contralateral cortex, hypothalamus and hippocampus. LEV administration on 6th day (dosage 50 mg/kg) did not have statistical effect on the epileptogenesis, while at a dosage of 200 mg/kg on 6th day LEV significantly suppressed paroxysmal activity in the studied structures of rats with cobalt epilepsy. The strongest anti-paroxysmal effect was detected in hippocampus and was expressed as the normalization of bioelectrical activity and the appearance of a regular theta rhythm. Thus, LEV effects are mostly directed to the hippocampal area of epileptiform activity and, to a lesser extent, to the cortical area.

Brivaracetam efficacy and safety in focal epilepsy

Introduction: Brivaracetam (BRV) is an analog of levetiracetam (LEV) with 15-30 times greater affinity to SV2A and greater brain permeability than LEV. These properties have stimulated interest in its clinical trial data and post-marketing experience. Areas covered: The authors provide a background on epilepsy and its treatment, discuss the racetam family of antiepileptic drugs to which BRV belongs, and then discuss BRV properties and its efficacy and tolerability in the treatment of epilepsy. Expert opinion: While preclinical data suggest a broad spectrum of efficacy, BRV is only approved for focal epilepsy. The recommended starting dose is 100 mg per day, but in the absence of urgency, it may be prudent to start at 50 mg per day, considered the lowest effective dose. There was no added benefit when BRV was used adjunctively with LEV in clinical trials. However, post-marketing data suggest that some patients may experience improved seizure control when switching from LEV. Behavioral adverse effects seemed less common than with LEV, and most patients switched to BRV after experiencing behavioral adverse effects on LEV reported improvement. Prior or anticipated intolerability to LEV is the strongest indication for BRV in clinical practice.

Age-Dependency of Levetiracetam Effects on Exocytotic GABA Release from Nerve Terminals in the Hippocampus and Cortex in Norm and After Perinatal Hypoxia

Perinatal hypoxia can lead to multiple chronic neurological deficits, e.g., mental retardation, behavioral abnormalities, and epilepsy. Levetiracetam (LEV), 2S-(2-oxo-1-pyrrolidiny1) butanamide, is an anticonvulsant drug with proven efficiency in treating patients with focal and generalized seizures. Rats were underwent hypoxia and seizures at the age of 10-12 postnatal days (pd). The ambient level and depolarization-induced exocytotic release of [³H]GABA (γ-aminobutyric acid) were analyzed in nerve terminals in the hippocampus and cortex during development at the age of pd 17-19 and pd 24-26 (infantile stage), pd 38-40 (puberty) and pd 66-73 (young adults) in norm and after perinatal hypoxia. LEV had no effects on the ambient [³H]GABA level. The latter increased during development and was further elevated after perinatal hypoxia in nerve terminals in the hippocampus during the whole period and in the cortex in young adults. Exocytotic [³H]GABA release from nerve terminals increased after perinatal hypoxia during development in the hippocampus and cortex, however this effect was preserved at all ages during blockage of GABA transporters by NO-711 in the hippocampus only. LEV realized its anticonvulsant effects at the presynaptic site through an increase in exocytotic release of GABA. LEV exerted more significant effect after perinatal hypoxia than in norm. Action of LEV was strongly age-dependent and can be registered in puberty and young adults, but the drug was inert at the infantile stage.

Levetiracetam for epilepsy: an evidence map of efficacy, safety and economic profiles

OBJECTIVE

To evaluate the efficacy, safety and economics of levetiracetam (LEV) for epilepsy.

MATERIALS AND METHODS

PubMed, Scopus, the Cochrane Library, OpenGrey.eu and ClinicalTrials.gov were searched for systematic reviews (SRs), meta-analyses, randomized controlled trials (RCTs), observational studies, case reports and economic studies published from January 2007 to April 2018. We used a bubble plot to graphically display information of included studies and conducted meta-analyses to quantitatively synthesize the evidence.

RESULTS

A total of 14,803 records were obtained. We included 30 SRs/meta-analyses, 34 RCTs, 18 observational studies, 58 case reports and 2 economic studies after the screening process. The included SRs enrolled patients with pediatric epilepsy, epilepsy in pregnancy, focal epilepsy, generalized epilepsy and refractory focal epilepsy. Meta-analysis of the included RCTs indicated that LEV was as effective as carbamazepine (CBZ; treatment for 6 months: 58.9% vs 64.8%, OR=0.76, 95% CI: 0.50-1.16; 12 months: 54.9% vs 55.5%, OR=1.24, 95% CI: 0.79-1.93), oxcarbazepine (57.7% vs 59.8%, OR=1.34, 95% CI: 0.34-5.23), phenobarbital (50.0% vs 50.9%, OR=1.20, 95% CI: 0.51-2.82) and lamotrigine (LTG; 61.5% vs 57.7%, OR=1.22, 95% CI: 0.90-1.66). SRs and observational studies indicated a low malformation rate and intrauterine death rate for pregnant women, as well as low risk of cognitive side effects. But psychiatric and behavioral side effects could not be ruled out. LEV decreased discontinuation due to adverse events compared with CBZ (OR=0.52, 95% CI: 0.41-0.65), while no difference was found when LEV was compared with placebo and LTG. Two cost-effectiveness evaluations for refractory epilepsy with decision-tree model showed US$ 76.18 per seizure-free day gained in Canada and US$ 44 per seizure-free day gained in Korea.

CONCLUSION

LEV is as effective as CBZ, oxcarbazepine, phenobarbital and LTG and has an advantage for pregnant women and in cognitive functions. Limited evidence supports its cost-effectiveness.

REGISTERED NUMBER

PROSPERO (No CRD 42017069367).

Mechanisms Underlying Aggressive Behavior Induced by Antiepileptic Drugs: Focus on Topiramate, Levetiracetam, and Perampanel

Antiepileptic drugs (AEDs) are effective against seizures, but their use is often limited by adverse effects, among them psychiatric and behavioral ones including aggressive behavior (AB). Knowledge of the incidence, risk factors, and the underlying mechanisms of AB induced by AEDs may help to facilitate management and reduce the risk of such side effects. The exact incidence of AB as an adverse effect of AEDs is difficult to estimate, but frequencies up to 16% have been reported. Primarily, levetiracetam (LEV), perampanel (PER), and topiramate (TPM), which have diverse mechanisms of action, have been associated with AB. Currently, there is no evidence for a specific pharmacological mechanism solely explaining the increased incidence of AB with LEV, PER, and TPM. Serotonin (5-HT) and GABA, and particularly glutamate (via the AMPA receptor), seem to play key roles. Other mechanisms involve hormones, epigenetics, and “alternative psychosis” and related phenomena. Increased individual susceptibility due to an underlying neurological and/or a mental health disorder may further explain why people with epilepsy are at an increased risk of AB when using AEDs. Remarkably, AB may occur with a delay of weeks or months after start of treatment. Information to patients, relatives, and caregivers, as well as sufficient clinical follow-up, is crucial, and there is a need for further research to understand the complex relationship between AED mechanisms of action and the induction/worsening of AB.

Severe hypoglycemia-induced sudden death is mediated by both cardiac arrhythmias and seizures

We previously demonstrated that insulin-induced severe hypoglycemia-associated sudden death is largely mediated by fatal cardiac arrhythmias. In the current study, a pharmacological approach was taken to explore the potential contribution of hypoglycemic seizures and the sympathoadrenergic system in mediating severe hypoglycemia-associated sudden death. Adult Sprague-Dawley rats were randomized into one of four treatment groups: 1) saline (SAL), 2) anti-arrhythmic (β₁ blocker atenolol), 3) antiseizure (levetiracetam), and 4) combination antiarrhythmic and antiseizure (β₁ Blocker+Levetiracetam). All rats underwent hyperinsulinemic severe hypoglycemic clamps for 3.5 h. When administered individually during severe hypoglycemia, β₁ blocker reduced 2nd and 3rd degree heart block by 7.7- and 1.6-fold, respectively, and levetiracetam reduced seizures 2.7-fold, but mortality in these groups did not decrease. However, it was combined treatment with both β₁ blocker and levetiracetam that remarkably reduced seizures and completely prevented respiratory arrest, while also eliminating 2nd and 3rd degree heart block, leading to 100% survival. These novel findings demonstrate that, in mediating sudden death, hypoglycemia elicits two distinct pathways (seizure-associated respiratory arrest and arrhythmia-associated cardiac arrest), and therefore, prevention of both seizures and cardiac arrhythmias is necessary to prevent severe hypoglycemia-induced mortality.

Levetiracetam-mediated improvement of decreased NMDA-induced glutamate release from nerve terminals during hypothermia

A combination of a beneficial neuroprotectant, hypothermia, with targeted medication is a perspective therapeutic approach. Here, we analyzed both non-specific (deep and profound hypothermia, 27 °C and 17 °C, respectively) and targeted (anticonvulsant drug levetiracetam) modulation of l-[¹⁴C]glutamate release induced by activation of presynaptic NMDA, AMPA, and kainate receptors in rat brain nerve terminals (synaptosomes). Gradual dynamics of hypothermia-mediated decrease in synaptosomal l-[¹⁴C]glutamate release evoked by the receptor agonists NMDA-, AMPA-, and kainate (250 μM) has been demonstrated that can be of value for the justification of optimal temperature regimes in therapeutic hypothermia. 250 μM NMDA-induced l-[¹⁴C]glutamate release from nerve terminals was higher in the presence of levetiracetam (100 μM) as compared to that without the drug. Despite levetiracetam effects decreased in hypothermia, combined application of hypothermia and levetiracetam resulted in higher NMDA-induced l-[¹⁴C]glutamate release from nerve terminals as compared to that without the drug. These effects were not revealed for synaptosomal AMPA- and kainate-induced l-[¹⁴C]glutamate release in the presence of levetiracetam at the similar concentration. Therefore, levetiracetam administration significantly mitigated a hypothermia-induced decrease in NMDA receptor response at the presynaptic level and can be used for the targeted neurocorrection to reduce side effects of hypothermia in cardiac surgery. However, levetiracetam-mediated improvement of NMDA receptor response is not applicable in stroke, brain trauma and neonatal asphyxia therapies, where the main neuroprotective action of hypothermia is associated with prevention of damaging consequence of pre-existing acute glutamate exitotoxicity.

Effect of levetiracetam on extracellular amino acid levels in the dorsal hippocampus of rats with temporal lobe epilepsy

Levetiracetam (LEV) is an anticonvulsant drug with a unique mechanism of action that is not completely understood. However, its activity profile may involve effects on excitatory and/or inhibitory neurotransmission since the primary target of LEV, synaptic vesicle protein 2A, is ubiquitously expressed in all types of synaptic vesicles. Therefore, the objective of the present study was to explore the effect of LEV (300 mg/kg/day for one week, administered via osmotic mini-pumps) on neurotransmitter release and its probable selective effect on extracellular gamma-amino butyric acid (GABA), glutamate (Glu), aspartate (Asp), glutamine (Gln), taurine (Tau) and glycine (Gly) concentrations (using in vivo microdialysis under basal and high-K⁺ conditions) in the dorsal hippocampus (DH), a region that undergoes major synaptic changes during epilepsy. Epileptic rats developed clear signs of hyperexcitability, i.e., an elevated Glu/GABA ratio in the DH. The LEV concentration in blood after 7 days of treatment was within the therapeutic range. In contrast, LEV was not detected four days after mini-pump removal (washout period). Furthermore, LEV restored the Glu/GABA ratio to approximately the control level and significantly increased the GABA concentration after the initiation of high-K⁺ conditions. Based on these data, LEV treatment restored the lost balance between the excitatory and inhibitory systems under basal conditions. Moreover, LEV showed a selective effect by preferentially increasing vesicular release of GABA, a mechanism by which LEV could reduce epileptic seizures.

Drug-Resistant Epilepsy and Surgery

BACKGROUND

Epilepsy is a chronic brain disease that is caused by various factors and characterized by recurrent, episodic and temporary central nervous system dysfunction which results due to excessive discharge of brain neurons. In the past decades, despite the continuous development of antiepileptic drugs, there are still many patients with epilepsy progressing to drugresistant epilepsy. Currently, surgical treatment is one of important way to cure drug-resistant epilepsy.

METHODS

Data were collected from Web of Science, Medline, Pubmed, through searching of these keywords: "surgery" and "drug-resistant epilepsy".

RESULTS

An increasing number of studies have shown that surgery plays an important role in the treatment of drug-resistant epilepsy. Moreover, the comprehensive treatment mainly based on surgery can achieve the remission and even cure of drug-resistant epilepsy.

CONCLUSION

In this review, we discuss the pathogenesis of drug-resistant epilepsy and the comprehensive treatment mainly based on surgery; this review may provide a reference for the clinical treatment of drug-resistant epilepsy.

Hallucination: A rare complication of levetiracetam theraphy

Levetiracetam is a new antiepileptic drug. In addition to epilepsy, it is also used for treating anxiety disorders and dystonia as well as tardive dyskinesia associated with the use of levodopa and neuroleptic drugs. Phenytoin therapy in a 10-year-old boy with convulsions was discontinued following cardiac rhythm impairment. The patient was then started on levetiracetam. However, visual and auditory hallucinations were observed on the 1st day of levetiracetam therapy. Levetiracetam was discontinued and replaced with sodium valproate, and the hallucinations resolved. The purpose of this report was to remind physicians that hallucinations are one of the rare complications of levetiracetam.

Brivaracetam does not modulate ionotropic channels activated by glutamate, γ-aminobutyric acid, and glycine in hippocampal neurons

Brivaracetam (BRV) is a selective, high-affinity ligand for synaptic vesicle protein 2A (SV2A), recently approved as adjunctive treatment for drug-refractory partial-onset seizures in adults. BRV binds SV2A with higher affinity than levetiracetam (LEV), and was shown to have a differential interaction with SV2A. Because LEV was reported to interact with multiple excitatory and inhibitory ligand-gated ion channels and that may impact its pharmacological profile, we were interested in determining whether BRV directly modulates inhibitory and excitatory ionotropic receptors in central neurons. Voltage-clamp experiments were performed in primary cultures of mouse hippocampal neurons. At a supratherapeutic concentration of 100 μm, BRV was devoid of any direct effect on currents gated by γ-aminobutyric acidergic type A, glycine, kainate, N-methyl-d-aspartate, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid. Similarly to LEV, BRV reveals a potent ability to oppose the action of negative modulators on the inhibitory receptors. In conclusion, these results show that BRV contrasts with LEV by not displaying any direct action on inhibitory or excitatory postsynaptic ligand-gated receptors at therapeutic concentrations and thereby support BRV's role as a selective SV2A ligand. These findings add further evidence to the validity of SV2A as a relevant antiepileptic drug target and emphasize the potential for exploring further presynaptic mechanisms as a novel approach to antiepileptic drug discovery.

Disposition of levetiracetam in healthy adult horses

Nine horses received 20 mg/kg of intravenous (LEV_IV ); 30 mg/kg of intragastric, crushed immediate release (LEV_CIR ); and 30 mg/kg of intragastric, crushed extended release (LEV_CER ) levetiracetam, in a three-way randomized crossover design. Crushed tablets were dissolved in water and administered by nasogastric tube. Serum samples were collected over 48 hr, and levetiracetam concentrations were determined by immunoassay. Mean ± SD peak concentrations for LEV_CIR and LEV_CER were 50.72 ± 10.60 and 53.58 ± 15.94 μg/ml, respectively. The y-intercept for IV administration was 64.54 ± 24.99 μg/ml. The terminal half-life was 6.38 ± 1.97, 7.07 ± 1.93 and 6.22 ± 1.35 hr for LEV_CIR , LEV_CER, and LEV_IV , respectively. Volume of distribution at steady-state was 630 ± 73.4 ml/kg. Total body clearance after IV administration was 74.40 ± 19.20 ml kg^-1  hr^-1 . Bioavailability was 96 ± 10, and 98 ± 13% for LEV_CIR and LEV_CER , respectively. A single dose of Levetiracetam (LEV) was well tolerated. Based on this study, a recommended dosing regimen of intravenous or oral LEV of 32 mg/kg every 12 hr is likely to achieve and maintain plasma concentrations within the therapeutic range suggested for humans, with optimal kinetics throughout the dosing interval in healthy adult horses. Repeated dosing and pharmacodynamic studies are warranted.