Cannabis and epilepsy.

BMJ Journals

“The one-third of people who do not gain seizure control through current treatment options need a revolution in epilepsy therapeutics.

The general population appears to be showing a fundamental and rapid shift in its opinion regarding cannabis and cannabis-related drugs. It is quite possible that cannabidiol, licensed in the USA for treating rare genetic epilepsies, may open the door for the widespread legalisation of recreational cannabis.

It is important that neurologists understand the difference between artisanal cannabidiol products available legally on the high street and the cannabidiol medications that have strong trial evidence.

In the UK in 2018 there are multiple high-profile reports of the response of children taking cannabis-derived medication, meaning that neurologists are commonly asked questions about these treatments in clinic. We address what an adult neurologist needs to know now, ahead of the likely licensing of Epidiolex in the UK in 2019.”

Translational Investigation of the Therapeutic Potential of Cannabidiol (CBD): Toward a New Age.

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“Among the many cannabinoids in the cannabis plant, cannabidiol (CBD) is a compound that does not produce the typical subjective effects of marijuana.

The aim of the present review is to describe the main advances in the development of the experimental and clinical use of cannabidiol CBD in neuropsychiatry.

CBD was shown to have anxiolytic, antipsychotic and neuroprotective properties. In addition, basic and clinical investigations on the effects of CBD have been carried out in the context of many other health conditions, including its potential use in epilepsy, substance abuse and dependence, schizophrenia, social phobia, post-traumatic stress, depression, bipolar disorder, sleep disorders, and Parkinson.

CBD is an useful and promising molecule that may help patients with a number of clinical conditions. Controlled clinical trials with different neuropsychiatric populations that are currently under investigation should bring important answers in the near future and support the translation of research findings to clinical settings.”

https://www.ncbi.nlm.nih.gov/pubmed/30298064

https://www.frontiersin.org/articles/10.3389/fimmu.2018.02009/full

Abuse potential assessment of cannabidiol (CBD) in recreational polydrug users: A randomized, double-blind, controlled trial.

“Treatment with a highly purified oral solution of cannabidiol (CBD), derived from the plant Cannabis sativa L., demonstrated some evidence of central nervous system (CNS)-related adverse events in patients enrolled in phase 3 trials for treatment of childhood-onset epilepsy. Cannabidiol was categorized as a Schedule 1 substance by the United States Drug Enforcement Administration; therefore, it was important to test CBD for human abuse potential.

Administration of a therapeutic dose of CBD (750 mg) showed significantly low abuse potential in a highly sensitive population of polydrug users. Although high and supratherapeutic doses of CBD (1500 mg and 4500 mg, respectively) had detectable subjective effects compared with placebo; the effects were significantly lower than those observed with alprazolam and dronabinol.

The majority of adverse events reported during the trial were of mild or moderate severity; no serious adverse events or deaths were reported.”

https://www.ncbi.nlm.nih.gov/pubmed/30286443

https://www.epilepsybehavior.com/article/S1525-5050(18)30483-9/fulltext

Potential Clinical Benefits of CBD-Rich Cannabis Extracts Over Purified CBD in Treatment-Resistant Epilepsy: Observational Data Meta-analysis.

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“This meta-analysis paper describes the analysis of observational clinical studies on the treatment of refractory epilepsy with cannabidiol (CBD)-based products. Beyond attempting to establish the safety and efficacy of such products, we also investigated if there is enough evidence to assume any difference in efficacy between CBD-rich extracts compared to purified CBD products.

The systematic search took place in February/2017 and updated in December/2017 using the keywords “epilepsy” or “Dravet” or “Lennox-Gastaut” or “CDKL5” combined with “Cannabis,” “cannabinoid,” “cannabidiol,” or “CBD” resulting in 199 papers.

The qualitative assessment resulted in 11 valid references, with an average impact factor of 8.1 (ranging from 1.4 to 47.8). The categorical data of a total of 670 patients were analyzed by Fischer test. The average daily dose ranged between 1 and 50 mg/kg, with treatment length from 3 to 12 months (mean 6.2 months).

Two thirds of patients reported improvement in the frequency of seizures (399/622, 64%). There were more reports of improvement from patients treated with CBD-rich extracts (318/447, 71%) than patients treated with purified CBD (81/223, 36%), with statistical significance (p < 0.0001).

Nevertheless, when the standard clinical threshold of a “50% reduction or more in the frequency of seizures” was applied, only 39% of the individuals were considered “responders,” and there was no difference (p = 0.56) between treatments with CBD-rich extracts (97/255, 38%) and purified CBD (94/223, 42%).

Patients treated with CBD-rich extracts reported lower average dose (6.1 mg/kg/day) than those using purified CBD (27.1 mg/kg/day). The reports of mild (109/285 vs. 291/346, p < 0.0001) and severe (23/285 vs. 77/346, p < 0.0001) adverse effects were more frequent in products containing purified CBD than in CBD-rich extracts.

CBD-rich extracts seem to present a better therapeutic profile than purified CBD, at least in this population of patients with refractory epilepsy. The roots of this difference is likely due to synergistic effects of CBD with other phytocompounds (aka Entourage effect), but this remains to be confirmed in controlled clinical studies.”

https://www.ncbi.nlm.nih.gov/pubmed/30258398

https://www.frontiersin.org/articles/10.3389/fneur.2018.00759/full

Cannabidiol for Treatment of Childhood Epilepsy-A Cross-Sectional Survey.

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“The interest in cannabidiol (CBD) for treatment of epilepsy has been increasing over the last years. However, practitioner’s attitudes concerning the use of CBD for epilepsy treatment appears to be divided and data about its clinical use in daily practice are not available.

Objective: To improve the knowledge about the current use of CBD amongst European practitioners treating children and adolescents for epilepsy.

Methods: Cross-sectional survey using an open-access online questionnaire for physicians treating children or adolescents for epilepsy within eight European countries from December 2017 to March 2018.

Results: One-hundred fifty-five physicians participated in the survey. CBD is increasingly used by 45% (69/155) of participants, treating a mean (range) number of 3 (1-35) with CBD. Only 48% of the participants prescribing CBD are exclusively using purified CBD to treat children and adolescents with epilepsy, the remainder also applies preparations containing delta9-tetrahydrocannabinol (THC). Reported daily CBD doses range from < 10 to 50 mg/kg body weight. Management of CBD therapy in regard of monitoring side effects and adjusting concomitant therapy differs widely amongst participants. Their primary objective for commencing CBD is improving patient’s quality of life. Participants frequently receive inquiries about CBD treatment but only 40% may actively suggest CBD as a treatment option. Of the 85 participants currently not using CBD for epilepsy treatment, 70% would consider using CBD if available in their country of practice or given the opportunity to become familiar with this treatment option.

Conclusions: CBD is increasingly used by participating physicians but individual experience remains limited. There are very diverse opinions about the use of CBD to treat epilepsy in children and adolescents and widely differing views on how to manage the CBD treatment.”

https://www.ncbi.nlm.nih.gov/pubmed/30258395

https://www.frontiersin.org/articles/10.3389/fneur.2018.00731/full

A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.

 Annals of Clinical and Translational Neurology banner

“Both Δ9 Tetrahydrocannabidiol (THC) and cannabidiol (CBD) components of cannabis, have been shown to have anticonvulsant effects.

Cannabis oils are used to treat seizures in drug-resistant epilepsy (DRE). Recent trials provide data on dosing, side effects, and efficacy of CBD, yet there is a paucity of information on THC in epilepsy.

Primary objective was to establish dosing and tolerability of TIL-TC150 – a cannabis plant extract produced by Tilray®, containing 100 mg/mL CBD and 2 mg/mL THC- in children with Dravet syndrome. Secondary objectives were to assess impact of therapy on seizures, electroencephalogram (EEG) and quality of life.

RESULTS:

Nineteen participants completed the 20-week intervention. Mean dose achieved was 13.3 mg/kg/day of CBD (range 7-16 mg/kg/day) and 0.27 mg/kg/day of THC (range 0.14-0.32 mg/kg/day). Adverse events, common during titration included somnolence, anorexia, and diarrhea. Abnormalities of liver transaminases and platelets were observed with concomitant valproic acid therapy. There was a statistically significant improvement in quality of life, reduction in EEG spike activity, and median motor seizure reduction of 70.6%, with 50% responder rate of 63%.

CONCLUSIONS:

TIL-TC150 was safe and well tolerated in our subjects. TIL-TC150 treatment resulted in a reduction in seizure counts, spike index on EEG, and improved quality of life measures. This study provides safety and dosing information for THC-containing cannabinoid preparations.”

https://www.ncbi.nlm.nih.gov/pubmed/30250864

https://onlinelibrary.wiley.com/doi/abs/10.1002/acn3.621

Inhibitory effects of cannabidiol on voltage-dependent sodium currents.

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“Cannabis sativa contains many related compounds known as phytocannabinoids. The main psychoactive and non-psychoactive compounds are Δ9-tetrahydrocannabidiol (THC) and cannabidiol (CBD), respectively.

Much of the evidence for clinical efficacy of CBD-mediated anti-epileptic effects has been from case reports or smaller surveys. The mechanisms for CBD’s anticonvulsant effects are unclear and likely involve non-cannabinoid receptor pathways.

CBD is reported to modulate several ion channels, including sodium channels (Nav). Evaluating therapeutic mechanisms and safety of CBD demands a richer understanding of its interactions with central nervous system targets. Here, we used voltage-clamp electrophysiology of HEK-293 cells and iPSC neurons to characterize the effects of CBD on Nav channels.

Our results show that CBD inhibits hNav1.1-1.7 currents, with an IC50 of 1.9-3.8 μM, suggesting that this inhibition could occur at therapeutically relevant concentrations. A steep Hill slope of ~3 suggested multiple interactions of CBD with Nav channels. CBD exhibited resting-state blockade, became more potent at depolarized potentials, and also slowed recovery from inactivation, supporting the idea that CBD binding preferentially stabilizes inactivated Nav channel states. We also found that CBD inhibits other voltage-dependent currents from diverse channels, including bacterial homomeric Nav channel (NaChBac) and voltage-gated potassium channel subunit Kv2.1. Lastly, the CBD block of Nav was temperature-dependent, with potency increasing at lower temperatures.

We conclude that CBD’s mode of action likely involves (1) compound partitioning in lipid membranes, which alters membrane fluidity affecting gating, and (2) undetermined direct interactions with sodium and potassium channels, whose combined effects are loss of channel excitability.”

https://www.ncbi.nlm.nih.gov/pubmed/30219789

http://www.jbc.org/content/early/2018/09/14/jbc.RA118.004929

Cannabis for the Treatment of Epilepsy: an Update.

“For millennia, there has been interest in the use of cannabis for the treatment of epilepsy.

However, it is only recently that appropriately powered controlled studies have been completed. In this review, we present an update on the research investigating the use of cannabidiol (CBD), a non-psychoactive component of cannabis, in the treatment of epilepsy.

While the anticonvulsant mechanism of action of CBD has not been entirely elucidated, we discuss the most recent data available including its low affinity for the endocannabinoid receptors and possible indirect modulation of these receptors via blocking the breakdown of anandamide.

Additional targets include activation of the transient receptor potential of vanilloid type-1 (TRPV1), antagonist action at GPR55, targeting of abnormal sodium channels, blocking of T-type calcium channels, modulation of adenosine receptors, modulation of voltage-dependent anion selective channel protein (VDAC1), and modulation of tumor necrosis factor alpha release.

We also discuss the most recent studies on various artisanal CBD products conducted in patients with epilepsy in the USA and internationally. While a high percentage of patients in these studies reported improvement in seizures, these studies were either retrospective or conducted via survey. Dosage/preparation of CBD was either unknown or not controlled in the majority of these studies.

Finally, we present data from both open-label expanded access programs (EAPs) and randomized placebo-controlled trials (RCTs) of a highly purified oral preparation of CBD, which was recently approved by the FDA in the treatment of epilepsy.

In the EAPs, there was a significant improvement in seizure frequency seen in a large number of patients with various types of treatment-refractory epilepsy. The RCTs have shown significant seizure reduction compared to placebo in patients with Dravet syndrome and Lennox-Gastaut syndrome. Finally, we describe the available data on adverse effects and drug-drug interactions with highly purified CBD.

While this product is overall well tolerated, the most common side effects are diarrhea and sedation, with sedation being much more common in patients taking concomitant clobazam. There was also an increased incidence of aspartate aminotransferase and alanine aminotransferase elevations while taking CBD, with many of the patients with these abnormalities also taking concomitant valproate. CBD has a clear interaction with clobazam, significantly increasing the levels of its active metabolite N-desmethylclobazam in several studies; this is felt to be due to CBD’s inhibition of CYP2C19. EAP data demonstrate other possible interactions with rufinamide, zonisamide, topiramate, and eslicarbazepine. Additionally, there is one case report demonstrating need for warfarin dose adjustment with concomitant CBD.

Understanding of CBD’s efficacy and safety in the treatment of TRE has expanded significantly in the last few years. Future controlled studies of various ratios of CBD and THC are needed as there could be further therapeutic potential of these compounds for patients with epilepsy.”

Acute foot-shock stress decreased seizure susceptibility against pentylenetetrazole-induced seizures in mice: Interaction between endogenous opioids and cannabinoids.

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“Stressful conditions affect the brain’s neurotransmission and neural pathways that are involved in seizure susceptibility. Stress alters the intensity and/or frequency of seizures.

Although evidence indicates that chronic stress exerts proconvulsant effects and acute stress has anticonvulsant properties, the underlying mechanisms which mediate these effects are not well understood.

In the present study, we assessed the role of endogenous opioids, endocannabinoids, as well as functional interaction between opioid and cannabinoid systems in the anticonvulsant effects of acute foot-shock stress (FSS) against pentylenetetrazole (PTZ)-induced seizures in mice.

CONCLUSIONS:

Opioid and cannabinoid systems are involved in the anticonvulsant effects of acute FSS, and these neurotransmission systems interact functionally in response to acute FSS.”

https://www.ncbi.nlm.nih.gov/pubmed/30170259

https://www.epilepsybehavior.com/article/S1525-5050(17)30777-1/fulltext

Anticonvulsant and Neuroprotective Effects of Cannabidiol During the Juvenile Period.

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“Anticonvulsant effects of cannabidiol (CBD), a nonpsychoactive cannabinoid, have not been investigated in the juvenile brain. We hypothesized that CBD would attenuate epileptiform activity at an age when the brain first becomes vulnerable to neurotoxicity and social/cognitive impairments.

To induce seizures, kainic acid (KA) was injected either into the hippocampus (KAih) or systemically (KAip) on postnatal (P) day 20. CBD was coadministered (KA + CBDih, KA + CBDip) or injected 30 minutes postseizure onset (KA/CBDih, KA/CBDip).

Hyperactivity, clonic convulsions, and electroencephalogram rhythmic oscillations were attenuated or absent after KA + CBDih and reduced after KA + CBDip. NeuN immunohistochemistry revealed neuroprotection.

Augmented reactive glia number and expression were reversed in CA1 but persisted deep within the dentate hilus. Parvalbumin-positive (PV+) interneurons were reduced in both models, whereas immunolabeling was dramatically increased within ipsilateral and contralateral dendritic/neuropilar fields following KA + CBDih. Cannabinoid receptor 1 (CB1) expression was minimally affected after KAih contrasting elevations observed after KAip.

Intracranial coadministration data suggest that CBD has higher efficacy in epilepsy with hippocampal focus rather than when extrahippocampal amygdala/cortical structures are triggered by systemic treatments. Inhibition of surviving PV+ and CB1+ interneurons may be facilitated by CBD implying a protective role in regulating hippocampal seizures and neurotoxicity at juvenile ages.”

https://www.ncbi.nlm.nih.gov/pubmed/30169677