Voltage gated sodium channel inhibitors as anticonvulsant drugs: A systematic review on recent developments and structure activity relationship studies

Evaluation of thiopyrano[2,3-d]thiazole derivatives as potential anticonvulsant agents

Anticonvulsant drug discovery has achieved significant progress; however, pharmacotherapy of epilepsy continues to be a challenge for modern medicine and pharmacy. To expand the chemical space of heterocycles as potential antiepileptic agents, herein we report on the synthesis and evaluation of anticonvulsant properties of a series of thiopyrano[2,3-d]thiazoles. The studied heterocycles are characterized by satisfactory drug-likeness and pharmacokinetics properties, calculated in silico using SwissADME. The anticonvulsant activity of thiopyrano[2,3-d]thiazole derivatives was evaluated in vivo using the subcutaneous pentylenetetrazole test. Three hits, that is, compounds 12, 14, and 16, that caused a pronounced anticonvulsant effect were identified. Derivatives 12, 14, and 16 positively affected the latent period of onset of clonic seizures, number of seizures, mortality rate, and duration of the seizure period of animals under experimental conditions. The anticonvulsant properties of compound 14 were equivalent to the effect of the reference drug, sodium valproate. All hit compounds are characterized by satisfying toxicity properties in the human lymphocytes and HEK293 cell line. The most active hit 14 possesses a potential affinity with the GABAA receptor in the molecular docking study and forms a stable complex in the molecular dynamics experiments equal to diazepam. Preliminary SAR results were obtained and discussed based on screening data.

Benzothiazole a privileged scaffold for Cutting-Edges anticancer agents: Exploring drug design, structure-activity relationship, and docking studies

Cancer is a major societal, public health, and economic burden in the 21st century, with 9.7 million deaths in 2022 (9.96 million in 2020) and 20 million new cancer cases (19.6 million in 2020). Considering the increasing number of cancer cases and deaths, heterocyclic compounds always paved the gold mine for the development of potential anticancer drugs as these compounds have unique flexibility and dynamic cores. Benzothiazoles and their derivatives have potential anticancer properties, making them a desirable scaffold among different heterocycles. Title structures are a class of chemicals that may bind to various receptors with high affinity, particularly those engaged in oncogenic processes. The use of these compounds allows medicinal chemists to rapidly produce anticancer treatments across a large range of targets over an extended length of time. The current study presents a thorough success story of benzothiazole derivatives as anticancer agents. It discusses the current state of cancer, the profile of benzothiazole-based derivatives synthetic pathways, and its relevance as an anticancer agent on several oncogenic pathways. The structure-activity relationship was also added to offer insight into the connection of biological data with structure and the rational design of more active drugs.

Poly (ADP-ribose) polymerase (PARP) inhibitors as anticancer agents: An outlook on clinical progress, synthetic strategies, biological activity, and structure-activity relationship

Poly (ADP-ribose) polymerase (PARP) is considered an essential component in case of DNA (Deoxyribonucleic acid) damage, response by sensing DNA damage and engaging DNA repair proteins. Those proteins repair the damaged DNA via an aspect of posttranslational modification, known as poly (ADP-Ribosyl)ation (PARylation). Specifically, PARP inhibitors (PARPi) have shown better results when administered alone in a variety of cancer types with BRCA (Breast Cancer gene) mutation. The clinical therapeutic benefits of PARP inhibitors have been diminished by their cytotoxicity, progression of drug resistance, and limitation of indication, regardless of their tremendous clinical effectiveness. A growing number of PARP-1 inhibitors, particularly those associated with BRCA-1/2 mutations, have been identified as potential cancer treatments. Recently, several researchers have identified various promising scaffolds, which have resulted in the resuscitation of the faith in PARP inhibitors as cancer therapies. This review provided a comprehensive update on the anatomy and physiology of the PARP enzyme, the profile of FDA (Food and Drug Administration) and CFDA (China Food and Drug Administration)-approved drugs, and small-molecule inhibitors of PARP, including their synthetic routes, biological evaluation, selectivity, and structure-activity relationship.

NF1 mutation-driven neuronal hyperexcitability sets a threshold for tumorigenesis and therapeutic targeting of murine optic glioma

BACKGROUND

With the recognition that noncancerous cells function as critical regulators of brain tumor growth, we recently demonstrated that neurons drive low-grade glioma initiation and progression. Using mouse models of neurofibromatosis type 1 (NF1)-associated optic pathway glioma (OPG), we showed that Nf1 mutation induces neuronal hyperexcitability and midkine expression, which activates an immune axis to support tumor growth, such that high-dose lamotrigine treatment reduces Nf1-OPG proliferation. Herein, we execute a series of complementary experiments to address several key knowledge gaps relevant to future clinical translation.

METHODS

We leverage a collection of Nf1-mutant mice that spontaneously develop OPGs to alter both germline and retinal neuron-specific midkine expression. Nf1-mutant mice harboring several different NF1 patient-derived germline mutations were employed to evaluate neuronal excitability and midkine expression. Two distinct Nf1-OPG preclinical mouse models were used to assess lamotrigine effects on tumor progression and growth in vivo.

RESULTS

We establish that neuronal midkine is both necessary and sufficient for Nf1-OPG growth, demonstrating an obligate relationship between germline Nf1 mutation, neuronal excitability, midkine production, and Nf1-OPG proliferation. We show anti-epileptic drug (lamotrigine) specificity in suppressing neuronal midkine production. Relevant to clinical translation, lamotrigine prevents Nf1-OPG progression and suppresses the growth of existing tumors for months following drug cessation. Importantly, lamotrigine abrogates tumor growth in two Nf1-OPG strains using pediatric epilepsy clinical dosing.

CONCLUSIONS

Together, these findings establish midkine and neuronal hyperexcitability as targetable drivers of Nf1-OPG growth and support the use of lamotrigine as a potential chemoprevention or chemotherapy agent for children with NF1-OPG.

Regioselective Synthesis of α-Quaternary Amino Acid Derivatives Enabled by Photoinduced Energy Transfer

α-Quaternary amino acids have found application in many biologically relevant compounds and pharmaceuticals. Although there are many methods for the synthesis of α-quaternary amino acids, most of them are mainly realized with the aid of transition metals and complex ligands. We present herein a 2,7-Br-4CzIPN catalyzed regioselective alkylation of azlactones with redox-active esters via radical-radical couplings. Strikingly, this approach is devoid of any metal or additive and shows broad scope and superior sensitive functional group compatibility.

Analysis of the action mechanisms and targets of herbal anticonvulsants highlights opportunities for therapeutic engagement with refractory epilepsy

Epilepsy is a neurological disorder characterized by spontaneous and recurring seizures. It poses significant therapeutic challenges due to diverse etiology, pathobiology, and pharmacotherapy-resistant variants. The anticonvulsive effects of herbal leads with biocompatibility and toxicity considerations have attracted much interest, inspiring mechanistic analysis with the view of their use for engagement of new targets and combination with antiseizure pharmacotherapies. This article presents a comprehensive overview of the key molecular players and putative action mechanisms of the most common antiepileptic herbals demonstrated in tissue culture and preclinical models. From the review of the literature, it emerges that their effects are mediated via five distinct mechanisms: (1) reduction of membrane excitability through inhibition of cation channels, (2) improvement of mitochondrial functions with antioxidant effects, (3) enhancement in synaptic transmission mediated by GABAA receptors, (4) improvement of immune response with anti-inflammatory action, and (5) suppression of protein synthesis and metabolism. While some of the primary targets and action mechanisms of herbal anticonvulsants (1, 3) are shared with antiseizure pharmacotherapies, herbal leads also engage with distinct mechanisms (2, 4, and 5), suggesting new drug targets and opportunities for their integration with antiseizure medications. Addressing outstanding questions through research and in silico modeling should facilitate the future use of herbals as auxiliary therapy in epilepsy and guide the development of treatment of pharmacoresistant seizures through rigorous trials and regulatory approval.

Synthetic product-based approach toward potential antileishmanial drug development

Leishmaniasis is a parasitic disease and is categorized as a tropically neglected disease (NTD) with no effective vaccines available. The available chemotherapeutics against leishmaniasis are associated with an increase in the incidence of toxicity and drug resistance. Consequently, targeting metabolic pathways and enzymes of parasites which differs from the mammalian host can be exploited to treat and overcome the resistance. The classical methods of identifying the structural fragments and the moieties responsible for the biological activities from the standard compounds and their modification are options for developing more effective novel compounds. Significant progress has been made in refining the development of potent non-toxic molecules and addressing the limitations of the current treatment available. Several examples of synthetic product-based approach utilizing their core heterocyclic rings including furan, pyrrole, thiazole, imidazole, pyrazole, triazole, quinazoline, quinoline, pyrimidine, coumarin, indole, acridine, oxadiazole, purine, chalcone, carboline, phenanthrene and metal containing derivatives and their structure-activity relationships are discussed in this review. It also analyses the groups/fragments interacting with the host cell receptors and will support the medicinal chemists with novel antileishmanial agents.

Anticonvulsant Classes and Possible Mechanism of Actions

Epilepsy is considered one of the most common neurological disorders worldwide; it needs long-term or life-long treatment. Despite the presence of several novel antiepileptic drugs, approximately 30% patients still suffer from drug-resistant epilepsy. Subsequently, searching for new anticonvulsants with lower toxicity and better efficacy is still in paramount demand. Using target-based studies in the discovery of novel antiepileptics is uncommon owing to the insufficient information on the molecular pathway of epilepsy and complex mode of action for most of known antiepileptic drugs. In this review, we investigated the properties of anticonvulsants, types of epileptic seizures, and mechanism of action for anticonvulsants.

Recent Progress in the Development of New Antiepileptic Drugs with Novel Targets

Background

Epilepsy is a chronic neurological disorder that affects approximately 50-70 million people worldwide. Epilepsy has a significant economic and social burden on patients as well as on the country. The recurrent, spontaneous seizure activity caused by abnormal neuronal firing in the brain is a hallmark of epilepsy. The current antiepileptic drugs provide symptomatic relief by restoring the balance of excitatory and inhibitory neurotransmitters. Besides, about 30% of epileptic patients do not achieve seizure control. The prevalence of adverse drug reactions, including aggression, agitation, irritability, and associated comorbidities, is also prevalent. Therefore, researchers should focus on developing more effective, safe, and disease-modifying agents based on new molecular targets and signaling cascades.

Summary

This review overviews several clinical trials that help identify promising new targets like lactate dehydrogenase inhibitors, c-jun n-terminal kinases, high mobility group box-1 antibodies, astrocyte reactivity inhibitors, cholesterol 24-hydroxylase inhibitors, glycogen synthase kinase-3 beta inhibitors, and glycolytic inhibitors to develop a new antiepileptic drug.

Key messages

Approximately 30% of epileptic patients do not achieve seizure control. The current anti-seizure drugs are not disease modifying, cure or prevent epilepsy. Lactate dehydrogenase inhibitor, cholesterol 24-hydroxylase inhibitor, glycogen synthase kinase-3 beta inhibitors, and mTOR inhibitors have a promising antiepileptogenic effect.

The sulfonadyns: a class of aryl sulfonamides inhibiting dynamin I GTPase and clathrin mediated endocytosis are anti-seizure in animal models

We show that dansylcadaverine (1) a known in-cell inhibitor of clathrin mediated endocytosis (CME), moderately inhibits dynamin I (dynI) GTPase activity (IC50 45 μM) and transferrin (Tfn) endocytosis in U2OS cells (IC50 205 μM). Synthesis gave a new class of GTP-competitive dynamin inhibitors, the Sulfonadyns™. The introduction of a terminal cinnamyl moiety greatly enhanced dynI inhibition. Rigid diamine or amide links between the dansyl and cinnamyl moieties were detrimental to dynI inhibition. Compounds with in vitro inhibition of dynI activity <10 μM were tested in-cell for inhibition of CME. These data unveiled a number of compounds, e.g. analogues 33 ((E)-N-(6-{[(3-(4-bromophenyl)-2-propen-1-yl]amino}hexyl)-5-isoquinolinesulfonamide)) and 47 ((E)-N-(3-{[3-(4-bromophenyl)-2-propen-1-yl]amino}propyl)-1-naphthalenesulfonamide)isomers that showed dyn IC50 <4 μM, IC50(CME) <30 μM and IC50(SVE) from 12-265 μM. Both analogues (33 and 47) are at least 10 times more potent that the initial lead, dansylcadaverine (1). Enzyme kinetics revealed these sulfonamide analogues as being GTP competitive inhibitors of dynI. Sulfonadyn-47, the most potent SVE inhibitor observed (IC50(SVE) = 12.3 μM), significantly increased seizure threshold in a 6 Hz mouse psychomotor seizure test at 30 (p = 0.003) and 100 mg kg-1 ip (p < 0.0001), with similar anti-seizure efficacy to the established anti-seizure medication, sodium valproate (400 mg kg-1). The Sulfonadyn™ class of drugs target dynamin and show promise as novel leads for future anti-seizure medications.

Iodine(III)-Mediated Oxidation of Anilines to Construct Dibenzazepines

The development of an efficient process that produces bioactive medium-sized N-heterocyclic scaffolds from 2-substituted anilines using either iodosobenzene or (bis(trifluoroacetoxy)iodo)-benzene is reported. The tether between the sulfonamide and the aryl group can be varied to access dihydroacridine-, dibenzazepine-, or dibenzazocine scaffolds. While substitution on the aniline portion is limited to electron-neutral- or electron-poor groups, a broader range of functional groups are tolerated on the ortho-aryl substituent and site selective C-NAr bond formation can be achieved. Preliminary mechanistic investigations suggest that medium-ring formation occurs via radical reactive intermediates.

Voltage-Gated Sodium Channel NaV1.7 Inhibitors with Potent Anticancer Activities in Medullary Thyroid Cancer Cells

Our results from quantitative RT-PCR, Western blotting, immunohistochemistry, and the tissue microarray of medullary thyroid cancer (MTC) cell lines and patient specimens confirm that VGSC subtype NaV1.7 is uniquely expressed in aggressive MTC and not expressed in normal thyroid cells and tissues. We establish the druggability of NaV1.7 in MTC by identifying a novel inhibitor (SV188) and investigate its mode of binding and ability to inhibit INa current in NaV1.7. The whole-cell patch-clamp studies of the SV188 in the NaV1.7 channels expressed in HEK-293 cells show that SV188 inhibited the INa current in NaV1.7 with an IC50 value of 3.6 µM by a voltage- and use-dependent blockade mechanism, and the maximum inhibitory effect is observed when the channel is open. SV188 inhibited the viability of MTC cell lines, MZ-CRC-1 and TT, with IC50 values of 8.47 μM and 9.32 μM, respectively, and significantly inhibited the invasion of MZ-CRC-1 cells by 35% and 52% at 3 μM and 6 μM, respectively. In contrast, SV188 had no effect on the invasion of TT cells derived from primary tumor, which have lower basal expression of NaV1.7. In addition, SV188 at 3 μM significantly inhibited the migration of MZ-CRC-1 and TT cells by 27% and 57%, respectively.

Riluzole and novel naphthalenyl substituted aminothiazole derivatives prevent acute neural excitotoxic injury in a rat model of temporal lobe epilepsy

Epileptogenic seizures, or status epilepticus (SE), leads to excitotoxic injury in hippocampal and limbic neurons in the kainic acid (KA) animal model of temporal lobe epilepsy (TLE). Here, we have further characterized neural activity regulated methylaminoisobutryic acid (MeAIB)/glutamine transport activity in mature rat hippocampal neurons in vitro that is inhibited by riluzole (IC₅₀ = 1 μM), an anti-convulsant benzothiazole agent. We screened a library of riluzole derivatives and identified SKA-41 followed by a second screen and synthesized several novel chlorinated aminothiazoles (SKA-377, SKA-378, SKA-379) that are also potent MeAIB transport inhibitors in vitro, and brain penetrant following systemic administration. When administered before KA, SKA-378 did not prevent seizures but still protected the hippocampus and several other limbic areas against SE-induced neurodegeneration at 3d. When SKA-377 - 379, (30 mg/kg) were administered after KA-induced SE, acute neural injury in the CA3, CA1 and CA4/hilus was also largely attenuated. Riluzole (10 mg/kg) blocks acute neural injury. Kinetic analysis of SKA-378 and riluzoles' blockade of Ca²⁺-regulated MeAIB transport in neurons in vitro indicates that inhibition occurs via a non-competitive, indirect mechanism. Sodium channel Na_V1.6 antagonism blocks neural activity regulated MeAIB/Gln transport in vitro (IC₅₀ = 60 nM) and SKA-378 is the most potent inhibitor of Na_V1.6 (IC₅₀ = 28 μM) compared to Na_V1.2 (IC₅₀ = 118 μM) in heterologous cells. However, pharmacokinetic analysis suggests that sodium channel blockade may not be the predominant mechanism of neuroprotection here. Riluzole and our novel aminothiazoles are agents that attenuate acute neural hippocampal injury following KA-induced SE and may help to understand mechanisms involved in the progression of epileptic disease.

Mechanisms of Transmission and Processing of Pain: A Narrative Review

Knowledge about the mechanisms of transmission and the processing of nociceptive information, both in healthy and pathological states, has greatly expanded in recent years. This rapid progress is due to a multidisciplinary approach involving the simultaneous use of different branches of study, such as systems neurobiology, behavioral analysis, genetics, and cell and molecular techniques. This narrative review aims to clarify the mechanisms of transmission and the processing of pain while also taking into account the characteristics and properties of nociceptors and how the immune system influences pain perception. Moreover, several important aspects of this crucial theme of human life will be discussed. Nociceptor neurons and the immune system play a key role in pain and inflammation. The interactions between the immune system and nociceptors occur within peripheral sites of injury and the central nervous system. The modulation of nociceptor activity or chemical mediators may provide promising novel approaches to the treatment of pain and chronic inflammatory disease. The sensory nervous system is fundamental in the modulation of the host's protective response, and understanding its interactions is pivotal in the process of revealing new strategies for the treatment of pain.

Design, synthesis of 1,2,4-triazine derivatives as antidepressant and antioxidant agents: In vitro, in vivo and in silico studies

The novel series of substituted-N-(5,6-diphenyl-1,2,4-triazin-3-yl) benzamides (R: 1-12) were designed, synthesized and evaluated for in-vitro and in-vivo antidepressant-like activity. In MAO-A inhibition assay, compound R: 5 and R: 9 displayed most potent activity with IC₅₀ = 0.12 and 0.30 µM. R: 5 and R: 9 were also evaluated for in-vivo antidepressant using FST and TST. In both models, the test samples R: 5 and R: 9 showed noteworthy antidepressant effect. R: 5 showed 46.48 % and 45.96 % reduction in immobility in FST and TST respectively at dosage of 30 mg/kg (p.o). Whereas compound R: 9 reduced the immobility time by 52.76 % and 47.14 % as compared to control in FST and TST, respectively at same dosage. Both the compounds were also tested for behavioural study using actophotometer and grip tests. None of compounds exhibited decrease in locomotor activity. Further, these compounds were subjected to in silico studies to determine their ADME properties along with binding energies and binding orientions. In ADME studies none of the compounds violated the Lipinski rule and all other parameters were also within the acceptable ranges. In docking study R: 5 (-10.7) and R: 9 (-10.4) were also displayed highest docking score. These encouraging results present the pharmacophoric features of substituted-N-(5,6-diphenyl-1,2,4-triazin-3-yl) benzamides as interesting lead for further development of new antidepressant drug molecules.

Coupling the Cardiac Voltage-Gated Sodium Channel to Channelrhodopsin-2 Generates Novel Optical Switches for Action Potential Studies

Voltage-gated sodium (Na⁺) channels respond to short membrane depolarization with conformational changes leading to pore opening, Na⁺ influx, and action potential (AP) upstroke. In the present study, we coupled channelrhodopsin-2 (ChR2), the key ion channel in optogenetics, directly to the cardiac voltage-gated Na⁺ channel (Na_v1.5). Fusion constructs were expressed in Xenopus laevis oocytes, and electrophysiological recordings were performed by the two-microelectrode technique. Heteromeric channels retained both typical Na_v1.5 kinetics and light-sensitive ChR2 properties. Switching to the current-clamp mode and applying short blue-light pulses resulted either in subthreshold depolarization or in a rapid change of membrane polarity typically seen in APs of excitable cells. To study the effect of individual K⁺ channels on the AP shape, we co-expressed either K_v1.2 or hERG with one of the Na_v1.5-ChR2 fusions. As expected, both delayed rectifier K⁺ channels shortened AP duration significantly. K_v1.2 currents remarkably accelerated initial repolarization, whereas hERG channel activity efficiently restored the resting membrane potential. Finally, we investigated the effect of the LQT3 deletion mutant ΔKPQ on the AP shape and noticed an extremely prolonged AP duration that was directly correlated to the size of the non-inactivating Na⁺ current fraction. In conclusion, coupling of ChR2 to a voltage-gated Na⁺ channel generates optical switches that are useful for studying the effect of individual ion channels on the AP shape. Moreover, our novel optogenetic approach provides the potential for an application in pharmacology and optogenetic tissue-engineering.

Inhibition of NaV1.7: the possibility of ideal analgesics

The selective inhibition of NaV1.7 is a promising strategy for developing novel analgesic agents with fewer adverse effects. Although the potent selective inhibition of NaV1.7 has been recently achieved, multiple NaV1.7 inhibitors failed in clinical development. In this review, the relationship between preclinical in vivo efficacy and NaV1.7 coverage among three types of voltage-gated sodium channel (VGSC) inhibitors, namely conventional VGSC inhibitors, sulphonamides and acyl sulphonamides, is discussed. By demonstrating the PK/PD discrepancy of preclinical studies versus in vivo models and clinical results, the potential reasons behind the disconnect between preclinical results and clinical outcomes are discussed together with strategies for developing ideal analgesic agents.

Synthesis and medicinal chemistry of tetronamides: Promising agrochemicals and antitumoral compounds

Butenolides and tetronic acids occupy a prominent position in synthetic chemistry due to their ubiquitous distribution in nature. This has stimulated investigations firstly in the synthesis of such systems and, laterly, the interest has turned to the understanding of the quantum structure of such systems, allowing a deeper understanding of the mechanism and reactivity of this cyclic scaffold. In contrast, tetronamides, which consist of compounds bearing a 4-aminofuran-2(5H)-one backbone, are relatively rare in nature and synthetic routes to such compounds are poorly explored. This review highlights both the importance of the tetronamide scaffold in medicinal chemistry and the most relevant recondite synthetic strategies for obtaining compounds of this class.

Effects of Antiarrhythmic Drugs on Antiepileptic Drug Action-A Critical Review of Experimental Findings

Severe cardiac arrhythmias developing in the course of seizures increase the risk of SUDEP (sudden unexpected death in epilepsy). Hence, epilepsy patients with pre-existing arrhythmias should receive appropriate pharmacotherapy. Concomitant treatment with antiarrhythmic and antiseizure medications creates, however, the possibility of drug–drug interactions. This is due, among other reasons, to a similar mechanism of action. Both groups of drugs inhibit the conduction of electrical impulses in excitable tissues. The aim of this review was the analysis of such interactions in animal seizure models, including the maximal electroshock (MES) test in mice, a widely accepted screening test for antiepileptic drugs.

Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction

Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.