New generation anticonvulsants for the treatment of epilepsy in children

Hypoxic-Ischemic Encephalopathy-Induced Seizure in an 11-Year-Old Female

Hypoxic-ischemic encephalopathy (HIE) typically manifests in the neonatal period. The degree of hypoxia following intrapartum asphyxia determines the structural changes in the brain, which can cause functional deficits in the affected child leading to developmental deficits and recurrent seizures. Management requires physical therapy, occupational therapy, and anti-seizure medications. We present a rare case of an 11-year-old female with a past medical history of epilepsy and cerebral atrophy secondary to hypoxic injury at birth. The patient presented to the hospital following a witnessed seizure and loss of consciousness for one hour. Given the past medical history and clinical findings, it was determined that a mild-to-moderate encephalopathic process resulted in a lower seizure threshold. HIE can manifest beyond the neonate years mainly due to the structural changes within the brain. Therefore, it is essential to understand aspects of HIE beyond the neonate years to manage this condition for a better patient outcome.

Development of novel indole-linked pyrazoles as anticonvulsant agents: A molecular hybridization approach

A series of 3-{2-[1-acetyl-5-(substitutedphenyl)-4,5-dihydropyrazol-3-yl]hydrazinylidene}-1,3-dihydro-2H-indol-2-ones 24-43 was synthesized using an appropriate synthetic route and evaluated experimentally by the maximal electroshock test. These compounds were evaluated for antidepressant and antianxiety activities. The most active compound, 3-{2-[1-acetyl-5-(4-chlorophenyl)-4,5-dihydropyrazol-3-yl]hydrazinylidene}-1,3-dihydro-2H-indol-2-one 25, exhibited an ED₅₀ of 13.19 mmol/kg, a TD₅₀ of 43.49 mmol/kg, and a high protective index of 3.29, compared with the standard drug diazepam. To get insights into the intermolecular interactions, molecular docking studies were performed at the active site of the GABA_A receptor and the MAO-A enzyme. Molecular docking studies are also in agreement with the pharmacological evaluation with potent compounds, exhibiting docking scores of -1.5180 and 0.7458 for the GABA_A receptor and MAO-A, respectively. The 3D-QSAR analysis was carried out by Vlife MDS engine 4.3.1, and a statistically reliable model with good predictive power (r²  = 0.7523, q²  = 0.3773) was achieved. The 3D-QSAR plots gave insights into the structure-activity relationship of these compounds, which may aid in the design of potent benzopyrrole derivatives as anticonvulsant agents. So, our research can make a great impact on those medicinal chemists who work on the development of anticonvulsant agents.

The Frequency and Clinical Features of Hypersensitivity Reactions to Antiepileptic Drugs in Children: A Prospective Study

BACKGROUND

Antiepileptic drugs (AEDs) can cause hypersensitivity reactions during childhood. Studies report a wide clinical spectrum of reactions with AED use, ranging from a mild rash to severe cutaneous reactions.

OBJECTIVE

To determine the prevalence and clinical features of AED hypersensitivity reactions during childhood.

METHODS

Patients in our pediatric neurology clinic who were prescribed an AED for the first time between November 2015 and November 2016 were monitored and those who developed skin rash during this period were evaluated.

RESULTS

A total of 570 patients were evaluated. The median age of the patients was 8.86 (interquartile range, 4.2-13.7) years, and 55.8% (318) of patients were male. The most frequently used AEDs were valproic acid (42%, n = 285) and carbamazepine (20.4%, n = 116). Hypersensitivity reactions to AEDs developed in 5.4% of patients. Of these patients, 71% (29) had cutaneous drug reactions and 29% (9) had severe cutaneous drug reactions; 61.3% (19) were using aromatic AEDs, and the leading suspected AED was carbamazepine (45.2%). Comparison of patients who did and did not develop AED hypersensitivity showed that hypersensitivity was more frequent among patients who were younger than 12 years, who used aromatic AEDs, or who used multiple AEDs. In addition, according to regression analysis results, aromatic AED use significantly increased the risk of AED hypersensitivity (P < .001).

CONCLUSIONS

Although allergic reactions to AEDs are rare, they are of significance because they can cause life-threatening severe cutaneous drug reactions. Therefore, patients receiving AEDs, especially aromatic AEDs, must be monitored closely.

Electrographic and pharmacological characterization of a progressive epilepsy phenotype in female MeCP2-deficient mice

Rett Syndrome is a neurodevelopmental disorder caused primarily by mutations in the gene encoding Methyl-CpG-binding protein 2 (MECP2). Spontaneous epileptiform activity is a common co-morbidity present in Rett syndrome, and hyper-excitable neural networks are present in MeCP2-deficient mouse models of Rett syndrome. In this study we conducted a longitudinal assessment of spontaneous cortical electrographic discharges in female MeCP2-deficient mice and defined the pharmacological responsiveness of these discharges to anti-convulsant drugs. Our data show that cortical discharge activity in female MeCP2-deficient mice progressively increases in severity as the mice age, with discharges being more frequent and of longer durations at 19-24 months of age compared to 3 months of age. Semiologically and pharmacologically, this basal discharge activity in female MeCP2-deficient mice displayed electroclinical properties consistent with absence epilepsy. Only rarely were convulsive seizures observed in these mice at any age. Since absence epilepsy is infrequently observed in Rett syndrome patients, these results indicate that the predominant spontaneous electroclinical phenotype of MeCP2-deficient mice we examined does not faithfully recapitulate the most prevalent seizure types observed in affected patients.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Anti-convulsant potential of quinazolinones

A series of novel quinazoline derivatives were virtually screened through different filters and evaluated for their anticonvulsant activity against electrically and chemically induced seizures.

New benzo[d]thiazol-2-yl-aminoacetamides as potential anticonvulsants: synthesis, activity and prediction of molecular properties

A series of N-(substituted-2-oxo-4-phenylazetidin-1-yl)-2-((6-substitutedbenzo[d]thiazol-2-yl)amino)acetamide derivatives were synthesized using pharmacophoric features with aromatic hydrophobic aryl ring (A), NH-C=O as hydrogen bonding domain, the nitrogen atom as electron donor (D), and phenyl as distal aryl ring (C). The synthesized molecules were initially screened for anticonvulsant activity using the maximal electroshock seizure (MES) test and the subcutaneous pentylenetetrazole test in albino mice. An acute neurotoxicity study on the synthesized molecules was also carried out using the rotarod test. The results of these tests revealed that two compounds, 5b and 5q, showed promising activity with ED50 values of 15.4 and 18.6 mg/kg and protective indices of 20.7 and 34.9 in the MES test, respectively, which are found to be approximately fourfold higher than those of the standard drugs phenytoin (6.9) and carbamazepine (8.1). These molecules may act as lead of the designed scheme. The pharmacokinetic profiles of all the synthesized compounds were estimated using Molinspiration software. None of the compounds violated Lipinski's "rule of five". The possible structure-activity relationship was discussed. In conclusion, this manuscript shows that the developed model has a highly prognostic power for the further investigation of better benzothiazole derivatives for future discovery and development.

Recent advances in the chemistry and biology of benzothiazoles

Benzothiazole is a privileged heterocyclic scaffold having a benzene ring fused with a five-membered thiazole ring. This moiety has attracted considerable attention because of its wide range of pharmacological activities such as antitubercular, antimicrobial, antimalarial, anticonvulsant, anthelmintic, analgesic, anti-inflammatory, antidiabetic, antitumor activity, etc. In the last few years, some novel benzothiazoles have been developed with varied biological activities. To access this scaffold in high yield and to introduce diversity, a variety of new synthetic methods have been invented. In this review, we highlight the development of novel benzothiazoles for various biological activities along with the best synthetic protocols for their synthesis.

Synthesis and anticonvulsant activity evaluation of 7-alkoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-ones

A new series of 7-alkoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-ones were synthesized and evaluated for their anticonvulsant activities. Among these compounds, 7-propoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-one (4c) and 7-butoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-one (4d) showed the highest activity against maximal electroshock (MES)-induced tonic extension [effective dose (ED)50 : 11.4 and 13.6 mg/kg, respectively]. It is worth mentioning that compound 4d showed especially low neurotoxicity, which led to a high protective index (PI >51). The orally anticonvulsant activity data of compound 4d further confirmed its efficacy, in an MES test, and its high safety with a PI value of 50.2. In addition, the potency of compound 4h against seizures induced by pentylenetetrazole, 3-mercaptopropionic acid, and bicuculline in the chemical-induced seizure tests suggested that compound 4d may exert its anticonvulsant activity through affecting the GABAergic system.

Synthesis and Anticonvulsant Evaluation of some New 6-(Substituted-phenyl)thiazolo[3,2-b][1,2,4]triazole Derivatives in Mice

Epilepsy is the most frequent nearological affiction and afflicts 1% about of the world's population. Currently there is an urgent need for the development of novel anticonvulsants with higher levels of potency and lower levels of toxicity. In this paper, a series of new 6-(substituted-phenyl)thiazolo[3,2-b][1,2,4]triazole derivatives were synthesized and tested for their anticonvulsant activities using the maximal electroshock (MES) and subcutaneous pentylenetetrazole (PTZ) screens, which are the most widely employed seizure models for early identification of candidate anticonvulsants. Their neurotoxicity was determined applying the rotarod test. In these compounds, 6-(4-fluorophenyl)thiazolo[3,2-b][1,2,4]triazole (3c) showed selective protection against the MES seizures with an ED50 value of 49.1 mg/Kg and a TD50 value of 94.1 mg/Kg, which provided compound 3c a protective index (PI = TD50/ED50) of 1.9 in the MES test. 6-(4-Propoxyphenyl)thiazolo[3,2-b][1,2,4]triazole (5b) was found to be active in both models, i.e. MES test and PTZ test. In the PTZ screen, compound 5b gave an ED50 of 63.4 mg/Kg and a TD50 of 105.6 mg/Kg, resulting in a PI value of 1.7 which is higher than carbamazepine.

Docking studies of phthalimide pharmacophore as a sodium channel blocker

OBJECTIVE(S)

Recently, phthalimide derivatives were designed based on ameltolide and thalidomide as they possess a similar degree of anticonvulsant potency due to their phenytoin-like profile. The ability of phthalimide pharmacophore to interact with neuronal voltage-dependent sodium channels was studied in the batrachotoxin affinity assay. Therefore, in the present study, a series of 19 compounds of phthalimide pharmacophore possessing a variety of substituents (NO2, NH2, Me, Cl, COOH, MeO) at 2-, 3-, and 4- position of the N-phenyl ring and N-(3-amino-2-methylphenyl) succinimide, were subjected to docking studies in order to inhibit voltage-gated sodium channels. Materials and Methods : Chemical structures of all compounds were designed using HYPERCHEM program and Conformational studies were performed through semi-empirical molecular orbital calculations method followed by PM3 force field. Total energy gradient calculated as a root mean square (RMS) value, until the RMS gradient was 0.01 kcal mol(-1). Among all energy minima conformers, the global minimum of compounds was used in docking calculations. Using a model of the open pore of Na channels, docking study was performed by AUTODOCK4.2 program. Results : Docking studies have revealed that these types of ligands interacted mainly with II-S6 residues of NaV1.2 through making hydrogen bonds and have additional hydrophobic interactions with domain I, II, III and IV in the channel's inner pore.

CONCLUSION

These computational studies have displayed that these compounds are capable of inhibiting Na channel, efficiently.

Synthesis and anticonvulsant activity evaluation of 8-alkoxy-5-(4H-1,2,4-triazol-4-yl)quinoline derivatives

Two series of 8-alkoxy-5-(4H-1,2,4-triazol-4-yl)quinolines and 8-alkoxy-5-(2H-1,2,4-triazol-3-one-4-yl)quinolines were synthesized. The anticonvulsant activity of these compounds was evaluated with maximal electroshock seizure test and rotarod test. Among the synthesized compounds, 8-octoxy-5-(4H-1,2,4-triazol-4-yl)quinoline (4g) was the most active compound with ED(50) of 8.80 mg/kg, TD(50) of 176.03 mg/kg and protective index of 20.0. Its neurotoxicity was lower than all other synthesized compounds and also markedly lower than that of the reference drug carbamazepine. In addition, the potency of compound 4g against seizures induced by pentylenetetrazole, 3-mercaptopropionic acid, and bicuculline suggested its broad spectrum activity, and the mechanisms of action including inhibition of voltage-gated ion channels and modulation of GABAergic activity might involve in its anticonvulsant activity.

Synthesis and evaluation of the anticonvulsant activity of 8-alkoxy-4,5-dihydrobenzo[b][1,2,4]triazolo[4,3-d][1,4]thiazepine derivatives

Two series of 8-alkoxy-4,5-dihydrobenzo[b][1,2,4]triazolo[4,3-d][1,4]thiazepine derivatives (6a-q and 7a-q) were synthesized and evaluated for their anticonvulsant activity using the maximal electroshock (MES) method. All of the compounds prepared were effective in the MES screens. Among which, compound 7j was considered as the most promising one with an ED50 value of 26.3 mg/kg and a superior protective index value of 12.6. The potency of compound 7j against seizures induced by pentylenetetrazole, 3-mercaptopropionic acid and bicuculline suggested that two different mechanisms of action might potentially be involved in its anticonvulsant activity, including the inhibition of voltage-gated ion channels and the modulation of GABAergic activity. A computational study was also conducted to predict the pharmacokinetic properties of the compounds prepared, with the results supporting the use of these compounds as a group of promising antiepileptic agents.

Design, synthesis, and anticonvulsant activity evaluation of 4-(3-alkoxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-ones

A series of 4-(3-alkoxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-ones were synthesized using the appropriate synthetic route and evaluated experimentally in the maximal electroshock test; their neurotoxicities were evaluated by the rotarod neurotoxicity test. The structures of these compounds were confirmed by IR, MS, (1) H-NMR, and elementary analysis. All target compounds exhibited anticonvulsant activity to varying degrees in the maximal electroshock test. 4-(3-Benzyloxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-one (4i) was the most promising compound with an ED(50) value of 30.5 mg/kg and a protective index (PI) of 18.63, showing a higher safety than the standard carbamazepine (PI=6.45). In addition, the potency of compound 4i against seizures induced by pentylenetetrazole and 3-mercaptopropionic acid suggested its broad-spectrum activity, and the mechanisms of action including inhibition of voltage-gated ion channels and modulation of GABAergic activity might be involved in its anticonvulsant activity.

Design and synthesis of novel 7-aminoquinazoline derivatives: antitumor and anticonvulsant activities

A novel series of 7-substituted-4(3H)-quinazolinone were designed, synthesized and evaluated for their antitumor and anticonvulsant activity. Compound 7 revealed broad-spectrum antitumor effectiveness toward numerous cell lines that belong to different tumor subpanels, whereas compounds 9 and 18 possess selective activity toward leukemia cell lines. Additionally, compounds 3, 15, 16, 18, 19 and 20 showed advanced anticonvulsant activity as well as lower neurotoxicity than reference drugs. The achieved results proved that the distinctive compounds could be valuable as a model for future devise, acclimatization and investigation to construct more active analogues.

Synthesis and anticonvulsant evaluation of some new 2,3,8-trisubstituted-4(3H)-quinazoline derivatives

A new series of 2,3,8-trisubstituted-4(3H)-quinazoline derivatives were synthesized, evaluated for their anticonvulsant activity against electrically (MES) and chemically (PTZ, picrotoxin and Strychnine) induced seizures and compared with the standard drugs methaqualone and sodium valproate. Compounds 3, 17 and 22 proved to be the most potent compounds of this series with relatively low neurotoxicity and low toxicity in the median lethal dose test as compared with the reference drugs. The obtained results showed that the most active compounds could be useful as a template for future design, modification and investigation to produce more active analogs.

A new generation of anticonvulsants for the treatment of epilepsy in children

Over the past 12 years, a number of new anticonvulsant drugs have been introduced for the treatment of childhood epilepsy. The present article reviews these new agents and provides the considerations one should use in selecting an antiepileptic drug for use in children. While in some cases the newer antiepileptic drugs have a more favourable pharmacokinetic and toxicity profile than the older drugs, there appears to be no objective evidence that any currently available antiepileptic drug is superior in terms of therapeutic efficacy.

Synthesis and anticonvulsant activity of 8-alkoxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one derivatives

A series of novel 8-alkoxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one derivatives were synthesized and screened for their anticonvulsant activities by the maximal electroshock (MES) test, subcutaneous pentylenetetrazol (scPTZ) test, and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). The results of these tests demonstrated that 8-heptyloxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3f) and 8-hexyloxy -5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3e) were the most promising compounds, with median effective dose (ED(50)) of 17.6 and 17.9 mg/kg, and protective index (PI) of greater than 63.4 and 62.4 in the MES test, respectively. These PI values were higher than the PI value of the prototype antiepileptic drug carbamazepine. The scPTZ test showed that 8-pentyloxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3d) was the most potent with ED(50) value of 38.0 mg/kg and PI value of greater than 29.4, which is much safer than marketed drug carbamazepine. The possible structure-activity relationship was discussed.

Selected Proceedings of the NICHD/FDA newborn drug development initiative: Part II

BACKGROUND

In February 2003, the National Institute of Child Health and Human Development (NICHD) and the US Food and Drug Administration (FDA) created the Newborn Drug Development Initiative (NDDI), an ongoing program to determine gaps in knowledge in neonatal therapeutics and to explore clinical study designs for use in the newborn population. Working groups were established in 3 therapeutic areas: the central nervous, pulmonary, and cardiovascular systems. Three additional groups discussed pain control, drug prioritization, and ethics in neonatal clinical trials.

OBJECTIVE

The purpose of this article was to provide an overview of the 5 articles written by members of the Neurology, Cardiology, Drug Prioritization, and Ethics Groups.

METHODS

Information for the current article, as well as the 5 articles presented in this supplemental section, was gathered from the proceedings of a workshop cosponsored by the NICHD and the FDA. This workshop took place March 29 and 30, 2004, in Baltimore, Maryland.

RESULTS

The Neurology Group addressed the treatment of 2 common and interrelated conditions in the newborn population: neonatal seizures and hypoxic-ischemic encephalopathy. The unsubstantiated clinical preference for using phenobarbital to treat neonatal seizures, coupled with the development of several newer antiepileptic drugs with application in children, dictates the need for rigorous clinical trials of these drugs in the neonatal population. A number of pharmacologic agents currently undergoing extensive investigations in experimental animals and adult humans may have application in the newborn population. The Cardiology Group reviewed controversial approaches to the diagnosis and treatment of cardiovascular instability of preterm infants and identified gaps in knowledge. The group discussed issues of study design and developed 2 study proposals: (1) a placebo-controlled trial with a rescue arm for symptomatic infants; and (2) a targeted blood pressure (BP) trial. The Drug Prioritization Group focused on the fact that the uniqueness of the newborn population is due to distinctive and changing physiologic characteristics, conditions, and diseases that are different from those affecting older children, as well as the large differences in developmental patterns between 23 weeks of gestation and term. All of these factors help explain the lack of adequate trials and the sparseness of evidence regarding efficacy and toxicity risks of most drugs used in the newborn population. Unfortunately, the frequency of drug use and polypharmacy is highest in very-low-birth-weight infants. The large number of drugs requiring study and the uniqueness of the indications for those drugs preclude the use of the prioritization process used in older children. The focus of the Drug Prioritization Group was the determination of factors that identify which drugs are most important for study. The Ethics Group was unique in that its members were integrated into the therapeutic groups. This approach allowed for the identification of similarities and dissimilarities in the proposed clinical trial design framework. The summary report included here identifies common themes voiced in the various NDDI reports and deliberations.

CONCLUSIONS

The 5 articles included in this issue address different issues but share common themes: the need to develop innovative trial designs and biomarkers of efficacy, consideration of ethical concerns, and selection of appropriate drugs for study.