An overview of third-generation antiseizure drugs: Clobazam, lacosamide, rufinamide, and vigabatrin

Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights

Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.

Liquid chromatographic methods for determination of the new antiepileptic drugs stiripentol, retigabine, rufinamide and perampanel: A comprehensive and critical review

The new antiepileptic drugs perampanel, retigabine, rufinamide and stiripentol have been recently approved for different epilepsy types. Being them an innovation in the antiepileptics armamentarium, a lot of investigations regarding their pharmacological properties are yet to be performed. Besides, considering their broad anticonvulsant activities, an extension of their therapeutic indications may be worthy of investigation, especially regarding other seizure types as well as other central nervous system disorders. Although different liquid chromatographic (LC) methods coupled with ultraviolet, fluorescence, mass or tandem-mass spectrometry detection have already been developed for the determination of perampanel, retigabine, rufinamide and stiripentol, new and more cost-effective methods are yet required. Therefore, this review summarizes the main analytical aspects regarding the liquid chromatographic methods developed for the analysis of perampanel, retigabine (and its main active metabolite), rufinamide and stiripentol in biological samples and pharmaceutical dosage forms. Furthermore, the physicochemical and stability properties of the target compounds will also be addressed. Thus, this review gathers, for the first time, important background information on LC methods that have been developed and applied for the determination of perampanel, retigabine, rufinamide and stiripentol, which should be considered as a starting point if new (bio)analytical techniques are aimed to be implemented for these drugs.

Association Between Adverse Events and Discontinuation of Antiepileptic Drugs Among Drug-Naïve Adults with Epilepsy

Background

Adherence to antiepileptic drugs (AEDs) remains the primary management tool to prevent recurrent seizures in patients with epilepsy. Adverse events associated with AEDs could have an impact on adherence and result in treatment failures.

Objective

The goal of this study was to assess the association between adverse events and discontinuation of AEDs for AED-naïve patients with epilepsy. Our second objective was to estimate the economic burden of AED discontinuation.

Methods

We retrospectively analyzed IBM MarketScan administrative data from 2014 to 2017. The cohort consisted of new users of AEDs with an epilepsy diagnosis and with two or more subsequent AED claims. Outpatient and inpatient cohorts were analyzed separately. Adverse events were identified by injury codes (E-CODES) or by International Classification of Diseases, Ninth/Tenth Edition (ICD-9/10) codes for disease manifestations reported in the literature or product inserts (LADE). Discontinuation of AEDs was defined as a gap of ≥ 60 days without a refill. All cost comparisons were based on 1:1 propensity-score matching. Associations between adverse events and discontinuation were estimated using logistic regression, adjusting for predefined covariates such as age, sex, Charlson Comorbidity Index, insurance type, and AED type.

Results

The overall discontinuation rate was 9% (E-CODES rate was 0.1% and LADE rate was 27%). The discontinued group was older (56.1 vs. 52.8 years; p < 0.0001). Adults aged ≥ 65 years had the highest discontinuation rate (11%). Patients who discontinued had fewer AED claims (6.8 vs. 9.2; p < 0.0001), more outpatient claims (19.3 vs. 17.8; p < 0.0001), and longer hospital stays (6.6 vs. 5.3 days; p < 0.0001). Differences in daily outpatient costs between patients with and without adverse events were statistically significant (E-CODES $US213 vs. 105; p = 0.001; LADE $US188 vs. 161; p < 0.0001). Additionally, total cost of AEDs in the outpatient cohort was higher for patients with adverse events (E-CODES and LADE). There was no association between E-CODES and AED discontinuation; however, there was a positive association between LADE and discontinuation in the outpatient cohort but a negative association in the inpatient cohort.

Conclusion

We found that total costs of prescriptions claimed and total costs of outpatient visits among the outpatient cohort were higher for those with adverse drug events than for those without. An association between adverse events and discontinuation was inconclusive because it depended on the target population and how the adverse events were identified.

Recent and Emerging Anti-seizure Drugs: 2013

OPINION STATEMENT

Recent and emerging pharmacotherapies have become available for use within the last 4 years to enhance our ability to manage people with epilepsy (PWE). More antiseizure drug (ASD) choices allow greater opportunity to match a unique medicine with each patient from the time of first seizure and for drug-resistant epilepsy. Balancing the efficacy, safety, and tolerability of an ASD is unique for each person and epilepsy syndrome. This tailored approach to effectiveness includes seven new ASDs that have become available since 2009 to treat PWE expanding our armamentarium to more than two dozen ASDs in the US that are now available for use. "Which ASD is best?" is still a complex challenge that remains to be answered. Until the ASD is found that is a panacea for everyone, the role of new AEDs in the treatment of epilepsy lies in the hands of the clinician to address the overall needs of the person first and foremost. In this paper, the newest and emerging ASDs in 2013 are reviewed focusing on the pharmacology, efficacy, and adverse effects. Each ASD has benefits and risks and the ultimate role in clinical use will be established over time as experience with each agent grows.