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Concept: Anticonvulsant


Neural stimulation can reduce the frequency of seizures in persons with epilepsy, but rates of seizure-free outcome are low. Vagus nerve stimulation prevents seizures by continuously activating noradrenergic projections from the brainstem to the cortex. Cortical norepinephrine then increases GABAergic transmission and increases seizure threshold. Another approach, responsive nervous stimulation, prevents seizures by reactively shocking the seizure onset zone in precise synchrony with seizure onset. The electrical shocks abort seizures before they can spread and manifest clinically. The goal of this study was to determine whether a hybrid platform in which brainstem activation triggered in response to impending seizure activity could prevent seizures. We chose the zebrafish as a model organism for this study because of its ability to recapitulate human disease, in conjunction with its innate capacity for tightly controlled high-throughput experimentation. We first set out to determine whether electrical stimulation of the zebrafish hindbrain could have an anticonvulsant effect. We found that pulse train electrical stimulation of the hindbrain significantly increased the latency to onset of pentylenetetrazole-induced seizures, and that this apparent anticonvulsant effect was blocked by noradrenergic antagonists, as is also the case with rodents and humans. We also found that the anticonvulsant effect of hindbrain stimulation could be potentiated by reactive triggering of single pulse electrical stimulations in response to impending seizure activity. Finally, we found that the rate of stimulation triggering was directly proportional to pentylenetetrazole concentration and that the stimulation rate was reduced by the anticonvulsant valproic acid and by larger stimulation currents. Taken as a whole, these results show that that the anticonvulsant effect of brainstem activation can be efficiently utilized by reactive triggering, which suggests that alternative stimulation paradigms for vagus nerve stimulation might be useful. Moreover, our results show that the zebrafish epilepsy model can be used to advance our understanding of neural stimulation in the treatment of epilepsy.

Concepts: Nervous system, Neurology, Cranial nerves, Epilepsy, Vagus nerve stimulation, Anticonvulsant, Seizure, Status epilepticus



To evaluate the risk of severe cutaneous adverse drug reactions (SCAR) after exposure to multi-indication antiepileptic drugs for in Korean elderly patients.

Concepts: Pharmacology, Illness, Epilepsy, Adverse drug reaction, Anticonvulsant, Benzodiazepine, Carbamazepine, Primidone


One quarter of deaths in Rett Syndrome (RTT), an X-linked neurodevelopmental disorder, are sudden and unexpected. RTT is associated with prolonged QTc interval (LQT), and LQT-associated cardiac arrhythmias are a potential cause of unexpected death. Standard of care for LQT in RTT is treatment with β-adrenergic antagonists; however, recent work indicates that acute treatment of mice with RTT with a β-antagonist, propranolol, did not prevent lethal arrhythmias. In contrast, acute treatment with a sodium channel blocker, phenytoin, prevented arrhythmias. Chronic dosing of propranolol may be required for efficacy; therefore, we tested the efficacy of chronic treatment with either propranolol or phenytoin on RTT mice. Phenytoin completely abolished arrhythmias, whereas propranolol showed no benefit. Surprisingly, phenytoin also normalized weight and activity, but worsened breathing patterns. To explore the role of sodium channel blockers on QT in people with RTT, we performed a retrospective analysis of QT status before and after sodium channel blocker antiepileptic therapies. Individuals with RTT and LQT significantly improved their QT interval status after being started on sodium channel blocker antiepileptic therapies. Thus, sodium channel blockers should be considered for the clinical management of LQT in individuals with RTT.

Concepts: Cardiology, Cardiac arrest, Cardiac electrophysiology, Long QT syndrome, QT interval, Anticonvulsant, Sodium channel blocker, Antiarrhythmic agents


Medically refractory epilepsy continues to be a challenge worldwide, and despite an increasing number of medical therapies, approximately 1 in 3 patients continues to have seizures. Cannabidiol (CBD), one of many constituents of the Cannabis sativa or marijuana plant, has received renewed interest in the treatment of epilepsy. While highly purified CBD awaits Food and Drug Administration (FDA) approval, artisanal formulations of CBD are readily available and are seeing increased use in our patient population. Although randomized controlled trials of CBD are ongoing and promising, data regarding artisanal formulations of CBD are minimal and largely anecdotal. Here, we report a retrospective study to define the efficacy of artisanal CBD preparations in children with epilepsy. Given the known interaction between CBD and clobazam, we also conducted a subgroup comparison to determine if clobazam use was related to any beneficial effects of CBD. Additionally, we compared response rates with CBD and with clobazam alone within an overlapping patient cohort. A pediatric cohort with epilepsy of 108 patients was identified through a medical record search for patients using CBD oil. The addition of CBD resulted in 39% of patients having a >50% reduction in seizures, with 10% becoming seizure-free. The responder rate for clobazam was similar. No patients achieved CBD monotherapy, although the weaning of other antiepileptic drugs (AEDs) became possible in 22% of patients. A comparable proportion had AED additions during CBD therapy. With concomitant use of clobazam, 44% of patients had a 50% reduction in seizures upon addition of CBD compared with 33% in the population not taking clobazam; this difference was not statistically significant. The most common reported side effect of CBD was sedation in less than 4% of patients, all of whom were also taking clobazam. Increased alertness and improved verbal interactions were reported in 14% of patients in the CBD group and 8% of patients in the CBD and clobazam group. Benefits were more marked in the CBD alone group, in contrast to the CBD and clobazam group, but this difference was not statistically significant. In summary, these findings support efficacy of artisanal CBD preparations in seizure reduction with few significant side effects. The response to CBD was independent of concurrent clobazam use, although clobazam may contribute to the sedation seen with concurrent CBD use.

Concepts: Pharmacology, Medicine, Randomized controlled trial, Epilepsy, Anticonvulsant, Seizure, Cannabis, Myoclonus


The relationship between monogenic and polygenic forms of epilepsy is poorly understood and the extent to which the genetic and acquired epilepsies share common pathways is unclear. Here, we use an integrated systems-level analysis of brain gene expression data to identify molecular networks disrupted in epilepsy.

Concepts: DNA, Gene, Genetics, Gene expression, Epilepsy, Anticonvulsant, Diazepam


The medium chain triglyceride ketogenic diet is an established treatment for drug-resistant epilepsy that increases plasma levels of decanoic acid and ketones. Recently, decanoic acid has been shown to provide seizure control in vivo, yet its mechanism of action remains unclear. Here we show that decanoic acid, but not the ketones β-hydroxybutryate or acetone, shows antiseizure activity in two acute ex vivo rat hippocampal slice models of epileptiform activity. To search for a mechanism of decanoic acid, we show it has a strong inhibitory effect on excitatory, but not inhibitory, neurotransmission in hippocampal slices. Using heterologous expression of excitatory ionotropic glutamate receptor AMPA subunits in Xenopus oocytes, we show that this effect is through direct AMPA receptor inhibition, a target shared by a recently introduced epilepsy treatment perampanel. Decanoic acid acts as a non-competitive antagonist at therapeutically relevant concentrations, in a voltage- and subunit-dependent manner, and this is sufficient to explain its antiseizure effects. This inhibitory effect is likely to be caused by binding to sites on the M3 helix of the AMPA-GluA2 transmembrane domain; independent from the binding site of perampanel. Together our results indicate that the direct inhibition of excitatory neurotransmission by decanoic acid in the brain contributes to the anti-convulsant effect of the medium chain triglyceride ketogenic diet.

Concepts: Protein, Neurology, Epilepsy, NMDA receptor, Anticonvulsant, Ligand-gated ion channel, Ketogenic diet, AMPA receptor


Antiepileptic drug treatment can induce psychosis in some patients. However, there are no agreed definitions or diagnostic criteria for antiepileptic drug-induced psychotic disorder in the classification systems of either epileptology or psychiatry. In this study we investigated the clinical spectrum of antiepileptic drug-induced psychotic disorder in patients with epilepsy. The medical records of all patients with epilepsy who were diagnosed by a neuropsychiatrist as having a psychotic disorder at the Royal Melbourne Hospital from January 1993 to June 2015 were reviewed. Data were extracted regarding epilepsy and its treatment, psychotic symptoms profile and outcome. The diagnosis of epilepsy was established in accordance to the classification system of the International League Against Epilepsy while that of psychotic disorder was made according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition and the proposal on neuropsychiatric disorders in epilepsy. Patients with antiepileptic drug-induced psychotic disorder were compared to those with psychotic disorders unrelated to antiepileptic drugs assessed over the same period (non-antiepileptic drug induced psychotic disorder group). Univariate comparisons were performed and variables with a value of P < 0.1 were selected for the multivariate logistic regression analysis. The records of 2630 in-patients and outpatients with epilepsy were screened, from which 98 (3.7%) with psychotic disorders were identified. Among these, 14 (14.3%) were diagnosed to have antiepileptic drug-induced psychotic disorder. Excluding one patient who developed psychosis after valproate withdrawal, 76.9% in the non-antiepileptic drug induced psychotic disorder group were female and the percentage of temporal lobe involvement was higher in the non-antiepileptic drug induced psychotic disorder group (69.2% versus 38.1%, P < 0.05). Current use of levetiracetam was higher in antiepileptic drug-induced psychotic disorder group (84.6% versus 20.2%, P < 0.01) while use of carbamazepine was higher in the comparator group (15.4% versus 44.0%, P < 0.05). Multivariate logistic regression confirmed four factors associated with antiepileptic drug-induced psychotic disorder: female gender, temporal lobe involvement and use of levetiracetam, and a negative association with carbamazepine. Disorganized behaviours and thinking were more common in the antiepileptic drug-induced psychotic disorder group (100% versus 72.6% and 76.9% versus 38.1%, respectively; P < 0.05). The percentage of continuous treatment with antipsychotic drugs was lower in the antiepileptic drug-induced psychotic disorder group (15.4% versus 66.7%, P < 0.01). No patients experienced a chronic course in antiepileptic drug-induced psychotic disorder group whereas 40.5% did in non-antiepileptic drug induced psychotic disorder (P < 0.05). Our findings indicated that one in seven patients with epilepsy who developed psychosis had antiepileptic drug-induced psychotic disorder. In these patients, female gender, temporal lobe involvement and current use of levetiracetam were significantly associated with antiepileptic drug induced psychotic disorder compared to other types of psychosis, while carbamazepine had a negative association. Disorganized behaviours and thinking were predominant in antiepileptic drug-induced psychotic disorder. Patients with antiepileptic drug-induced psychotic disorder differed from non-antiepileptic drug-induced psychotic disorders in having better outcome.

Concepts: Epilepsy, Anticonvulsant, Schizophrenia, Psychosis, Bipolar disorder, Psychiatry, Benzodiazepine, Valproic acid


To identify potential pharmacokinetic interactions between the pharmaceutical formulation of cannabidiol (CBD; Epidiolex) and the commonly used antiepileptic drugs (AEDs) through an open-label safety study. Serum levels were monitored to identify interactions between CBD and AEDs.

Concepts: Pharmacology, Drug, Anticonvulsant, Barbiturate, Pharmaceutical formulation


The syndrome of malignant migrating partial seizures of infancy (MMPSI) is characterized by early onset of multiple seizure types and overall poor prognosis. Seizures are markedly drug resistant and few reports have suggested the efficacy of some antiepileptic drugs. We report one case of MMPSI in which prolonged seizure control is obtained with an association of clonazepam, levetiracetam and stiripentol, confirming thus the possibility of complete sustained seizure control in this epileptic syndrome. Of more than 60 cases reported to date, ours is the forth in which sustained complete control of seizures was obtained.

Concepts: Epilepsy, Anticonvulsant, Seizure, Status epilepticus, Absence seizure, Complex partial seizure, Diazepam, Atonic seizure