Second-line cannabis therapy in patients with epilepsy.

OBJECTIVE: Marijuana-based therapies (MBTs) have been shown to reduce seizure frequency in patients with severe and drug-resistant epilepsy (DRE). Pharmaceutical-grade CBD (EpidiolexⓇ) was approved by the FDA in 2018 for the treatments of Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS) and subsequently in 2020 for tuberous sclerosis complex (TSC). It is unclear what the utility would be in prescribing one type of MBT if a previous, alternative type failed. We conducted a retrospective study to determine if an alternative formulation of MBT reduces seizure frequency if the patient has not had a meaningful response from an initial MBT. We also investigated the clinical impact that a second MBT has on side effect profile. METHODS: We reviewed the charts of patients with DRE who were at least 2 years old and who took at least 2 different formulations of MBT, including a pharmacologic formulation of CBD (EpidiolexⓇ), artisanal marijuana, and/or a hemp-based formulation. We reviewed medical records in patients 2 years of age and older; however, subjects' historical data, such as age of first seizure onset, may be prior to the age of 2 years. We extracted data on demographics, type of epilepsy, history of epilepsy, medication history, seizure count, and drug side effects. Seizure frequency, side effect profiles, and predictors of responder status were evaluated. RESULTS: Thirty patients were identified as taking more than 1 type of MBT. Our findings suggest that seizure frequencies do not change significantly from baseline to after the first MBT and to after the second MBT (p = .4). However, we did find that patients with greater baseline seizure frequency were significantly more likely to respond to treatment after the second MBT (p = .03). To our second endpoint of side effect profile, we found that patients who experienced side effects after a second MBT had significantly greater seizure frequency compared to those who did not (p = .04). CONCLUSION: We found no significant seizure frequency reduction from baseline to after a second MBT in patients who tried at least 2 different formulations of MBT. This suggests a low probability of seizure frequency reduction with a second MBT therapy in patients with epilepsy who tried at least two different MBTs. While these findings need to be replicated in a larger sample, they suggest that clinicians should not delay care by trying alternative MBT formulations after a patient has already tried one. Instead, it may be more prudent to attempt an alternative class of therapy.

Therapeutic and clinical foundations of cannabidiol therapy for difficult-to-treat seizures in children and adults with refractory epilepsies.

Novel and effective antiseizure medications are needed to treat refractory and rare forms of epilepsy. Cannabinoids, which are obtained from the cannabis plant, have a long history of medical use, including for neurologic conditions. In 2018, the US Food and Drug Administration approved the first phytocannabinoid, cannabidiol (CBD, Epidiolex), which is now indicated for severe seizures associated with three rare forms of developmental and epileptic encephalopathy: Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Compelling evidence supports the efficacy of CBD in experimental models and patients with epilepsy. In randomized clinical trials, highly-purified CBD has demonstrated efficacy with an acceptable safety profile in children and adults with difficult-to-treat seizures. Although the underlying antiseizure mechanisms of CBD in humans have not yet been elucidated, the identification of novel antiseizure targets of CBD preclinically indicates multimodal mechanisms that include non-cannabinoid pathways. In addition to antiseizure effects, CBD possesses strong anti-inflammatory and neuroprotective activities, which might contribute to protective effects in epilepsy and other conditions. This article provides a succinct overview of therapeutic approaches and clinical foundations of CBD, emphasizing the clinical utility of CBD for the treatment of seizures associated with refractory and rare epilepsies. CBD has shown to be a safe and effective antiseizure medicine, demonstrating a broad spectrum of efficacy across multiple seizure types, including those associated with severe epilepsies with childhood onset. Despite such promise, there are many perils with CBD that hampers its widespread use, including limited understanding of pharmacodynamics, limited exposure-response relationship, limited information for seizure freedom with continued use, complex pharmacokinetics with drug interactions, risk of adverse effects, and lack of expert therapeutic guidelines. These scientific issues need to be resolved by further investigations, which would decide the unique role of CBD in the management of refractory epilepsy.

O uso do canabidiol em crianças com epilepsia resistente a medicamento e a diminuição na frequência das crises: revisão rápida / The use of cannabidiol in children with drug-resistant epilepsy and the decrease in the frequency of seizures: quick review

Uso de canabidiol (CDB) medicinal presente no óleo de canabis. Indicação: Tratamento de crianças portadoras de epilepsia refratária resistente a medicação e síndromes graves decorrentes. Pergunta: O uso do canabidiol em crianças com epilepsia resistente a medicamentos apresentaria diminuição na frequência de crises convulsivas? Objetivo: Investigar a eficácia e a segurança do canabidiol, em comparação a placebo, na manutenção da remissão em crianças com epilepsia refratária. Métodos: Revisão rápida de revisões sistemáticas, por meio de buscas bibliográficas realizadas nas bases PUBMED, SCOPUS, BVS, Cochrane Library. Foram utilizadas estratégias de buscas com vocabulário padronizado e avaliação da qualidade metodológica usando o checklist AMSTAR 2. Resultados: Foram selecionadas duas revisões sistemáticas que atendiam aos critérios de elegibilidade. O CDB quando comparado ao placebo reduziu 50% das convulsões para epilepsia refrataria (RR 1.69 [1.20 ­ 2.36]), para a síndrome de Lennox-Gastaut o RR foi 2.98 (IC 95%, 1.83 - 4.85) e para a síndrome de Dravet o RR foi 2.26 (IC 95% ,1.38 - 3.70). O CDB pode resultar em uma diminuição no apetite em dosagens maiores (RR = 2,10, IC 95% [0,96­4,62], embora não apresente diferença de efeito dos grupos comparadores. Conclusão: Duas revisões sistemáticas recentes o CDB quando comparado ao placebo reduziu 50% das convulsões para epilepsia refrataria e síndromes graves. Entretanto, existem poucos ensaios clínicos publicados na área

: Use of cannabidiol (CBD) present in cannabis oil. Indication: Treatment of children with drug-resistant refractory epilepsy and severe syndromes resulting. Question: Would the use of cannabidiol in children with drug-resistant epilepsy lead to a decrease in seizure frequency? Objective: to investigate the efficacy and safety of cannabidiol, compared to placebos, in maintaining remission in children with refractory epilepsy. Methods: Rapid review of systematic reviews, through a bibliographical search carried out in the PUBMED, SCOPUS, BVS, Cochrane Library databases. Predefined search strategies were followed, and the methodological quality of the included studies was evaluated using the AMSTAR 2 tool. Results: Two systematic reviews were selected, which met the eligibility criteria. CBD when compared to placebo reduce 50% of seizures for refractory epilepsy (RR 1.69, IC 95% [1.20 ­ 2.36]), for Lennox-Gastaut Syndrome the RR was foi 2.98 (IC 95%, 1.83 - 4.85) and for Dravet Syndrome o RR FOI 2.26 (IC 95% ,1.38 - 3.70). CBD may result in appetite decrease using high doses (RR = 2.10, 95% IC [0.96­ 4.62], with no statistical difference. Conclusion: Two recent systematics, CBD, when compared to placebo, presented 50% of seizures for refractory epilepsy and severe syndromes. However, there are few clinical trials published in the area

Uso del cannabis medicinal en niños con encefalopatías epilépticas farmacorresistentes. Experiencia en Hospital Garrahan / Use of medicinal cannabis in children with drug-resistant epileptic encephalopathies. Experience at Garrahan Hospital

Objetivo: Reportamos resultados sobre la efectividad, seguridad y tolerancia del cannabidiol como adyuvante terapéutico en pacientes pediátricos con encefalopatías epilépticas del desarrollo (EED) resistentes al tratamiento farmacológico y no farmacológico tras un seguimiento promedio de 20 meses. Métodos: Se realizó un estudio de cohorte prospectivo para evaluar la eficacia, la seguridad y la tolerancia del aceite de cannabis medicinal enriquecido con CBD añadido a los medicamentos anticonvulsivos estándar en niños con EED resistentes a los medicamentos atendidos en un único centro. Resultados: Entre octubre de 2018 y marzo de 2020, se incluyeron 59 pacientes. La edad media en el momento del inicio del protocolo fue de 10,5 años (rango, 2-17 años). La mediana de la duración del tratamiento fue de 20 meses (rango, 12-32). La mediana de edad en el momento de la primera convulsión fue de 8 meses (rango, 1 día - 10 años). Al final del seguimiento, el 78% de los niños tenía una disminución ≥ 50% en frecuencia de las crisis y el 47,5% tenía una disminución > 75%. Siete pacientes (11,9%) estaban libres de convulsiones. El número de crisis se redujo de una mediana de 305/mes a 90/mes, que supone una reducción media del 57% y una mediana del 71% (p < 0,0001). Los efectos adversos fueron en su mayoría leves o moderados. El CBD se interrumpió en 17 pacientes (28,8%) por falta de respuesta al tratamiento, aumento de la frecuencia de las convulsiones, intolerancia al fármaco o cumplimiento terapéutico insuficiente. Conclusión: En los niños con EED resistentes a los fármacos, el tratamiento a largo plazo del cannabis medicinal enriquecido con CBD como terapia adyuvante resultó ser seguro, bien tolerado y eficaz. Las reducciones sostenidas en la frecuencia de las convulsiones y la mejora de los aspectos de la vida diaria se observaron en comparación con nuestros preliminares (AU)

Objective: We report results on the effectiveness, safety, and tolerance of cannabidiol (CBD) as add-on therapy in children with developmental and epileptic encephalopathies (DEE) resistant to pharmacological and non-pharmacological treatment after a mean follow-up of 20 months. Methods: A prospective cohort study was conducted to evaluate the efficacy, safety, and tolerability of CBD-enriched medical cannabis oil added to standard antiseizure medications in children with drug-resistant DEEs seen at a single center. Results: Between October 2018 and March 2020, 59 patients were included. The median age at protocol initiation was 10.5 years (range, 2-17 years). Median treatment duration was 20 months (range, 12-32). The median age at the time of the first seizure was 8 months (range, 1 day - 10 years). At the end of follow-up, 78% of the children had a decrease ≥ 50% in seizure frequency and 47.5% had a decrease of > 75%. Seven patients (11.9%) were seizure free. The number of seizures was reduced from a median of 305/month to 90/month, accounting for a mean reduction of 57% and a median of 71% (p < 0.0001). Adverse effects were mostly mild or moderate. CBD was discontinued in 17 patients (28.8%) due to lack of response to treatment, increased seizure frequency, drug intolerance, or poor compliance. Conclusion: In children with drug-resistant DEE, long-term treatment with CBD-enriched medicinal cannabis as add-on therapy proved to be safe, well tolerated, and effective. Sustained reductions in seizure frequency and improvement in aspects of daily living were observed compared to our preliminary results (AU)

Use of cannabidiol in the treatment of epilepsy.

INTRODUCTION: Cannabis sativa has been cultivated for human use for about 5,000 years, and has likewise been used in the treatment of epilepsy for thousands of years. STATE OF THE ART: Cannabidiol (CBD), which was isolated from cannabis sativa in 1940, has an anti-seizure effect and no psychoactive activity. Its effectiveness in reducing various types of seizures has been proven in animal seizure and epilepsy models. Recent randomised, placebo-controlled trials have confirmed its effectiveness in patients with drug-resistant epilepsy. CLINICAL IMPLICATIONS: The aim of this position paper was to present the specific mechanism of CBD's anti-seizure action and current indications for CBD's use in epilepsy. The only cannabis-derived drug that has successfully passed clinical trials and has obtained United States Food and Drug Administration and European Medicines Agency approval for epilepsy is Epidiolex®. This paper presents the outcomes of the completed clinical trials with the use of this drug. FUTURE DIRECTIONS: CBD may be an effective drug in drug-resistant epilepsy, particularly in Dravet Syndrome, Lennox- Gastaut Syndrome and seizures associated with tuberous sclerosis complex. Additional randomised, placebo-controlled studies with CBD are needed.

Cannabidiol for the treatment of Lennox-Gastaut syndrome and Dravet syndrome: experts' recommendations for its use in clinical practice in Spain. / Cannabidiol para el tratamiento del síndrome de Lennox-Gastaut y del síndrome de Dravet: recomendaciones de expertos sobre su uso en la práctica clínica en España.

INTRODUCTION: Cannabidiol (CBD) is one of the main components of the cannabis plant that has demonstrated anti-epileptic seizure effect. Following its clinical development, in September 2019 the European Medicines Agency approved its indication for the adjunctive therapy of epileptic seizures associated with Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS), combined with clobazam (CLB), in patients of 2 years of age and older. AIM: To establish recommendations on the use of plant-derived highly purified CBD on which Spanish experts have reached consensus for the treatment of epilepsy in patients with DS and LGS based on their clinical experience and the scientific evidence. DEVELOPMENT: Consensus meeting with the participation of four Spanish neurologists and neuropediatric who are experts in epilepsy secondary to DS and LGS and with clinical experience in the use and management of CBD. They discussed on several topics, including posology (starting dose, dose escalation schema), efficacy (assessment of outcomes and indications for treatment withdrawal), and safety (evaluation, drug-drug interactions, adverse events management). CONCLUSIONS: In order to optimise CBD treatment, a slow dose escalation (= 4 weeks) is recommended until the maximum recommended dose or the desire effect is reached. It is also recommended that the concomitant antiseizure medications (ASMs) be reduced in case of adverse events due to interactions, and that the treatment continues for at least 6 months if it is well tolerated. The efficacy and safety of CBD must be assessed individually, considering the benefits and risks for individual patients.

TITLE: Cannabidiol para el tratamiento del síndrome de Lennox-Gastaut y del síndrome de Dravet: recomendaciones de expertos sobre su uso en la práctica clínica en España.Introducción. El cannabidiol (CBD) es uno de los componentes principales de la planta del cannabis que ha demostrado efecto ante las crisis epilépticas. Tras su desarrollo clínico, obtuvo su aprobación por la Agencia Europea del Medicamento en septiembre de 2019 para el tratamiento de las crisis epilépticas asociadas con el síndrome de Lennox-Gastaut (SLG) y el síndrome de Dravet (SD), en combinación con el clobazam (CLB), en pacientes a partir de los dos años. Objetivo. Establecer unas recomendaciones de manejo del CBD derivado de la planta altamente purificado consensuadas por expertos españoles en el tratamiento de la epilepsia para su uso en pacientes con SD y SLG, basándose en su experiencia clínica y en la evidencia científica. Desarrollo. Reunión de consenso de un grupo de cuatro neurólogos y neuropediatras españoles expertos en el manejo de la epilepsia asociada al SD y el SLG y con experiencia clínica en el uso de CBD. Se debatió sobre diferentes áreas, incluyendo la posología (dosis de inicio, pauta de escalada), la eficacia (valoración de resultados e indicaciones para la suspensión del tratamiento) y la seguridad (evaluación, interacciones entre fármacos, manejo de efectos adversos). Conclusiones. Para optimizar el tratamiento con CBD, se recomienda una pauta lenta de escalada de dosis (de cuatro semanas o más) hasta alcanzar la dosis máxima recomendada o el efecto deseado, reducir los fármacos anticrisis epilépticas concomitantes si aparecen efectos adversos por interacciones y mantener el tratamiento al menos seis meses si se tolera. La eficacia y la seguridad del CBD deben evaluarse de forma individual, considerando el beneficio y el riesgo para cada paciente.

Highly Purified Cannabidiol for Epilepsy Treatment: A Systematic Review of Epileptic Conditions Beyond Dravet Syndrome and Lennox-Gastaut Syndrome.

BACKGROUND: Cannabidiol (CBD), which is one major constituent of the Cannabis sativa plant, has anti-seizure properties and does not produce euphoric or intrusive side effects. A plant-derived, highly purified CBD formulation with a known and constant composition has been approved by the US Food and Drug Administration for the treatment of seizures associated with Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. In the European Union, the drug has been authorized by the European Medicines Agency for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome, in conjunction with clobazam, and is under regulatory review for the treatment of seizures in patients with tuberous sclerosis complex. OBJECTIVES: This systematic review aimed to summarize the currently available body of knowledge about the use of this US Food and Drug Administration/European Medicines Agency-approved oral formulation of pharmaceutical-grade CBD in patients with epileptic conditions, especially developmental and epileptic encephalopathies other than Dravet syndrome and Lennox-Gastaut syndrome. METHODS: The relevant studies were identified through MEDLINE and the US National Institutes of Health Clinical Trials Registry in October 2020. There were no date limitations or language restrictions. The following types of studies were included: clinical trials, cohorts, case-control, cross-sectional, clinical series, and case reports. Participants had to meet the following criteria: any sex, any ethnicity, any age, diagnosis of epilepsy, receiving plant-derived, highly purified (> 98% w/w) CBD in a sesame oil-based oral solution for the treatment of seizures. Data extracted from selected records included efficacy, tolerability, and safety outcomes. RESULTS: Five hundred and seventy records were identified by database and trial register searching. Fifty-seven studies were retrieved for detailed assessment, of which 42 were eventually included for the review. The participants of the studies included patients of both pediatric and adult age. Across the trials, purified CBD was administered at dosages up to 50 mg/kg/day. In a randomized double-blind controlled trial in patients with tuberous sclerosis complex, CBD was associated with a significantly greater percent reduction in seizure frequency than placebo over the treatment period. Open-label studies suggested the effectiveness of CBD in the treatment of children and adults presenting with other epilepsy syndromes than those addressed by regulatory trials, including CDKL5 deficiency disorder and Aicardi, Dup15q, and Doose syndromes, SYNGAP1 encephalopathy, and epilepsy with myoclonic absences. The most common adverse events observed during treatment with CBD included somnolence, decreased appetite, diarrhea, and increased serum aminotransferases. CONCLUSIONS: The currently available data suggest that response to treatment with a highly purified, plant-derived CBD oil-based solution can be seen in patients across a broad range of epilepsy disorders and etiologies. The existing evidence can provide preliminary support for additional research.

Interaction of cannabidiol with other antiseizure medications: A narrative review.

OBJECTIVE: Cannabidiol is efficacious as an adjunctive treatment in children with epilepsy associated with Dravet and Lennox-Gastaut syndromes. As its role is currently adjunctive, we reviewed the interactions of cannabidiol with other antiseizure medications (ASMs). METHODS: A search of Cochrane, Pubmed and Embase databases from January 2015 to April 2020 was performed. All original research papers discussing interactions between cannabidiol and ASMs were included. Bibliographies of review articles were searched to identify further papers. Adverse events and side effects were excluded. RESULTS: Cannabidiol interacts with ASMs through both pharmacokinetic and pharmacodynamic mechanisms. Thirty studies were identified (eighteen observational cohort studies, two randomised-control trials, three case reports/series, three animal studies, two briefing reports, an analysis of cohort data and a clinical trial simulation). There is potential for pharmacokinetic interactions between CBD and brivaracetam, clobazam, eslicarbazepine, lacosamide, gabapentin, oxcarbazepine, phenobarbital, potassium bromide, pregabalin, rufinamide, sirolimus/everolimus, stiripentol, tiagabine, topiramate and zonisamide. Pharmacodynamic interactions were identified for clobazam, valproate and levetiracetam. An animal study identified that the brain concentration of ASMs may be altered while the serum concentration remains the same. CONCLUSION: Pharmacokinetic and pharmacodynamic interactions exist between cannabidiol and ASMs. The cytochrome p450 system in particular has been implicated in pharmacokinetic interactions, although not exclusively. The existing literature is limited for some ASMs by studies having relatively small cohorts. As increasing numbers of patients use cannabidiol, specialists need to monitor closely for interactions clinically and with blood levels when required.

Cannabidiol Interactions with Medications, Illicit Substances, and Alcohol: a Comprehensive Review.

Cannabidiol, a non-intoxicating phytocannabinoid, has potential therapeutic effects over a broad range of disorders. Recently, there has been increased interest in CBD, as several studies showed promising anticonvulsant efficacy with few side effects. In 2018, a CBD-based oral solution, Epidiolex®, was approved by the FDA to treat two severe forms of pediatric epilepsy, Dravet syndrome, and Lennox-Gastaut syndrome. Although only these two syndromes are recognized indications for CBD, it has been consumed in an unregulated fashion for a variety of indications including chronic pain, muscle stiffness, inflammation, anxiety, smoking cessation, and even cancer. While CBD legislation in the USA is confusing due to the differences in state and federal laws, CBD has proliferated in the US market in several forms such as CBD oil or capsules, hemp oil/extract, and also as an ingredient in several dietary supplements, syrups, teas, and creams. With the ever-increasing use of CBD and its widespread availability to the general public, it is important to examine and report on possible drug-drug interactions between CBD and other therapeutic agents as well as addictive substances such as alcohol and tobacco. A detailed literature search for CBD's possible interactions was conducted using online databases. As expected, CBD has been reported to interact with anti-epileptic drugs, antidepressants, opioid analgesics, and THC, but surprisingly, it interacts with several other common medications, e.g. acetaminophen, and substances including alcohol. This review provides a comprehensive list of interacting drugs. The possible mechanisms for these drug-drug interactions are presented in table format. Given the growing popularity of CBD as a medication and the dearth of available information on CBD drug-drug interactions, it is critical to be aware of current drug-drug interactions and it will be important to investigate the impact of CBD upon concomitant medication use in future randomized, controlled trials.

Cannabidiol Therapy for Refractory Epilepsy and Seizure Disorders.

Cannabis-derived cannabinoids have neuroactive properties. Recently, there has been emerging interest in the use of cannabidiol (CBD)-enriched products for treatment of drug-resistant epilepsy. In 2018, the FDA approved the use of CBD-rich Epidiolex for two severe forms of epilepsy in children (Lennox-Gastaut and Dravet syndromes). Experimental research supports the use of CBD in many CNS disorders, though the mechanisms underlying its anticonvulsant and neuroprotective effects remain unclear. CBD has been shown to reduce inflammation, protect against neuronal loss, normalize neurogenesis, and act as an antioxidant. These actions appear to be due to the multimodal mechanism of action of CBD in the brain. This chapter briefly describes the current information on cannabis pharmacology with an emphasis on the clinical utility of CBD in the treatment of refractory epilepsies and other related seizure conditions. Clinical trials are ongoing for other forms of epilepsy and refractory seizures associated with infantile spasms, tuberous sclerosis, and Rett syndrome. Overall, adjunct CBD has been found to be generally safe and effective for treatment-resistant seizures in children with severe early-onset epilepsy. Whether an add-on CBD is efficacious for the long-term treatment of various epilepsy and seizure types in adults being tested in various clinical trials.

Development of cannabidiol as a treatment for severe childhood epilepsies.

In recent years, there has been a growing appreciation by regulatory authorities that cannabis-based medicines can play a useful role in disease therapy. Although often conflagrated by proponents of recreational use, the legislative rescheduling of cannabis-derived compounds, such as cannabidiol (CBD), has been associated with the steady increase in the pursuit of use of medicinal cannabis. One key driver in this interest has been the scientific demonstration of efficacy and safety of CBD in randomised, placebo-controlled clinical trials in children and young adults with difficult-to-treat epilepsies, which has encouraged increasing numbers of human trials of CBD for other indications and in other populations. The introduction of CBD as the medicine Epidiolex in the United States (in 2018) and as Epidyolex in the European Union (in 2019) as the first cannabis-derived therapeutic for the treatment of seizures was underpinned by preclinical research performed at the University of Reading. This work was awarded the British Pharmacological Society Sir James Black Award for Contributions to Drug Discovery 2019 and is discussed in the following review article.

Advances in the Treatment of Drug-Resistant Pediatric Epilepsy.

Epilepsy is a common disorder in children and adults that causes significant morbidity and affects many aspects of a patient's lives. Two-thirds of patients with epilepsy are controlled with established antiseizure medications, leaving a significant number of patients searching for other options. The purpose of this review is to provide an overview of recent advancements in the management of treatment-resistant epilepsy in pediatric patients. Recent publications have shown the efficacy of new pharmaceutical options such as fenfluramine and cannabidiol, some of which have been tested specifically in patients with childhood-onset epilepsy syndromes such as Dravet's syndrome and Lennox-Gastaut's syndrome. Furthermore, recent approval by the U.S. Food and Drug Administration of stiripentol has made available a previously difficult-to-obtain option for patients with Dravet's syndrome. Finally, implanted responsive neurostimulation devices for direct cortical stimulation and deep brain stimulation have shown efficacy in adult patients and may represent a thrilling new horizon for pediatric patients.

Epilepsy and cannabidiol: a guide to treatment.

The growing interest in cannabidiol (CBD), specifically a pure form of CBD, as a treatment for epilepsy, among other conditions, is reflected in recent changes in legislation in some countries. Although there has been much speculation about the therapeutic value of cannabis-based products as an anti-seizure treatment for some time, it is only within the last two years that Class I evidence has been available for a pure form of CBD, based on placebo-controlled RCTs for patients with Lennox-Gastaut syndrome and Dravet syndrome. However, just as we are beginning to understand the significance of CBD as a treatment for epilepsy, in recent years, a broad spectrum of products advertised to contain CBD has emerged on the market. The effects of these products are fundamentally dependent on the purity, preparation, and concentration of CBD and other components, and consensus and standardisation are severely lacking regarding their preparation, composition, usage and effectiveness. This review aims to provide information to neurologists and epileptologists on the therapeutic value of CBD products, principally a purified form, in routine practice for patients with intractable epilepsy.

Source of cannabinoids: what is available, what is used, and where does it come from?

Cannabis sativa L. is an ancient medicinal plant wherefrom over 120 cannabinoids are extracted. In the past two decades, there has been increasing interest in the therapeutic potential of cannabis-based treatments for neurological disorders such as epilepsy, and there is now evidence for the medical use of cannabis and its effectiveness for a wide range of diseases. Cannabinoid treatments for pain and spasticity in patients with multiple sclerosis (Nabiximols) have been approved in several countries. Cannabidiol (CBD), in contrast to tetra-hydro-cannabidiol (THC), is not a controlled substance in the European Union, and over the years there has been increasing use of CBD-enriched extracts and pure CBD for seizure disorders, particularly in children. No analytical controls are mandatory for CBD-based products and a pronounced variability in CBD concentrations in commercialized CBD oil preparations has been identified. Randomized controlled trials of plant-derived CBD for treatment of Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) have provided evidence of anti-seizure effects, and in June 2018, CBD was approved by the Food and Drug Administration as an add-on antiepileptic drug for patients two years of age and older with LGS or DS. Medical cannabis, with various ratios of CBD and THC and in different galenic preparations, is licensed in many European countries for several indications, and in July 2019, the European Medicines Agency also granted marketing authorisation for CBD in association with clobazam, for the treatment of seizures associated with LGS or DS. The purpose of this article is to review the availability of cannabis-based products and cannabinoid-based medicines, together with current regulations regarding indications in Europe (as of July 2019). The lack of approval by the central agencies, as well as social and political influences, have led to significant variation in usage between countries.

The role of cannabinoids in epilepsy treatment: a critical review of efficacy results from clinical trials.

CBD was shown to have anti-seizure activity based on in vitro and in vivo models. However, several reports of small series or case reports of the use of cannabis extracts in epilepsy yielded contradictory results and the efficacy of cannabis use in patients with epilepsy have also been inconclusive. In 2013, the first Phase 1 trial for a purified form of CBD (Epidiolex/Epidyolex; >99% CBD), developed by GW Pharma, showed some efficacy signals and subsequently, a comprehensive program on the efficacy and tolerability of this compound for the treatment of drug-resistant epilepsies was initiated. Results of these trials led to the FDA and EMA approval respectively in 2018 and 2019 for the treatment of seizures associated with two rare epilepsies: Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) in patients two years of age and older. Thus, CBD became the first FDA-approved purified drug substance derived from cannabis and also the first FDA-approved drug for the treatment of seizures in DS. We detail the clinical studies using purified CBD (Epidiolex/Epidyolex), including the first open interventional exploratory study and Randomized Control Ttrials for DS and LGS.

A perspective on cannabinoids for treating epilepsy: Do they really change the landscape?

With the licensing of cannabidiol for drug resistant seizures in Dravet and Lennox Gastaut syndromes in the United states in 2018, interest in the potential for cannabis-based-medicinal products to meet currently unmet needs for people with epilepsy continues to grow. This review summarizes current knowledge and discusses the implications for future research and practice. Both cannabidiol and tetrahydrocannabinol, the main components, have been extensively studied in animal models, with multimodal mechanisms of action proposed. Only pure cannabidiol formulations have been rigorously evaluated in controlled trials thus far, with modest but significant improvements in motor seizures. Adverse effects include diarrhoea, somnolence and reduced appetite, with mostly acceptable tolerability, but a not insignificant (up to 1 in 23) risk of serious adverse events. Recognized drug interactions include with valproate (increased risk of hepatotoxicity) and clobazam (contributing to somnolence, increased secretions, probably chest infections, and potentially efficacy). Whilst there is public (and producer) interest in products also containing tetrahydrocannabinol, clinicians have justifiable concerns about exposing a group already vulnerable to mental health and neurobehavioural comorbidities to the associated additional risks in these domains. Artisanal preparations, with often inconsistent/unknown constituents are frequently used but not recommended. A gulf exists between the actual evidence, including a lack of comparative studies and public beliefs, fuelled by media and anecdote. Continued education of the public, policymakers, researchers and healthcare providers about what is and isn't yet known, together with on-going good quality research is essential to mitigate against future potential risks, particularly in relation to vulnerable populations. 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'.

Personalized medicine: Vinpocetine to reverse effects of GABRB3 mutation.

OBJECTIVE: To screen a library of potential therapeutic compounds for a woman with Lennox-Gastaut syndrome due to a Y302C GABRB3 (c.905A>G) mutation. METHODS: We compared the electrophysiological properties of cells with wild-type or the pathogenic GABRB3 mutation. RESULTS: Among 1320 compounds, multiple candidates enhanced GABRB3 channel conductance in cell models. Vinpocetine, an alkaloid derived from the periwinkle plant with anti-inflammatory properties and the ability to modulate sodium and channel channels, was the lead candidate based on efficacy and safety profile. Vinpocetine was administered as a dietary supplement over 6 months, reaching a dosage of 20 mg three times per day, and resulted in a sustained, dose-dependent reduction in spike-wave discharge frequency on electroencephalograms. Improved language and behavior were reported by family, and improvements in global impression of change surveys were observed by therapists blinded to intervention. SIGNIFICANCE: Vinpocetine has potential efficacy in treating patients with this mutation and possibly other GABRB3 mutations or other forms of epilepsy. Additional studies on pharmacokinetics, potential drug interactions, and safety are needed.

Pharmacological and Therapeutic Properties of Cannabidiol for Epilepsy.

Cannabidiol (CBD) is a major active component of the Cannabis plant, which, unlike tetrahydrocannabinol (THC), is devoid of euphoria-inducing properties. During the last 10 years, there has been increasing interest in the use of CBD-enriched products for the treatment of epilepsy. In 2018, an oil-based highly purified liquid formulation of CBD (Epidiolex) derived from Cannabis sativa was approved by the US Food and Drug Administration for the treatment of seizures associated with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). The mechanisms underlying the antiseizure effects of CBD are unclear but may involve, among others, antagonism of G protein-coupled receptor 55 (GPR55), desensitization of transient receptor potential of vanilloid type 1 (TRPV1) channels, and inhibition of adenosine reuptake. CBD has complex and variable pharmacokinetics, with a prominent first-pass effect and a low oral bioavailability that increases fourfold when CBD is taken with a high-fat/high-calorie meal. In four randomized, double-blind, parallel-group, adjunctive-therapy trials, CBD given at doses of 10 and 20 mg/kg/day administered in two divided administrations was found to be superior to placebo in reducing the frequency of drop seizures in patients with LGS and convulsive seizures in patients with DS. Preliminary results from a recently completed controlled trial indicate that efficacy also extends to the treatment of seizures associated with the tuberous sclerosis complex. The most common adverse events that differentiated CBD from placebo in controlled trials included somnolence/sedation, decreased appetite, increases in transaminases, and diarrhea, behavioral changes, skin rashes, fatigue, and sleep disturbances. About one-half of the patients included in the DS and LGS trials were receiving concomitant therapy with clobazam, and in these patients a CBD-induced increase in serum levels of the active metabolite norclobazam may have contributed to improved seizure outcomes and to precipitation of some adverse effects, particularly somnolence.

Cannabis effects on brain structure, function, and cognition: considerations for medical uses of cannabis and its derivatives.

Background: Cannabis is the most widely used illicit substance worldwide, and legalization for recreational and medical purposes has substantially increased its availability and use in the United States.Objectives: Decades of research have suggested that recreational cannabis use confers risk for cognitive impairment across various domains, and structural and functional differences in the brain have been linked to early and heavy cannabis use.Methods: With substantial evidence for the role of the endocannabinoid system in neural development and understanding that brain development continues into early adulthood, the rising use of cannabis in adolescents and young adults raises major concerns. Yet some formulations of cannabinoid compounds are FDA-approved for medical uses, including applications in children.Results: Potential effects on the trajectory of brain morphology and cognition, therefore, should be considered. The goal of this review is to update and consolidate relevant findings in order to inform attitudes and public policy regarding the recreational and medical use of cannabis and cannabinoid compounds.Conclusions: The findings point to considerations for age limits and guidelines for use.