Cannabidiol exerts antiepileptic effects by restoring hippocampal interneuron functions in a temporal lobe epilepsy model.

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“A non-psychoactive phytocannabinoid, cannabidiol (CBD), shows promising results as an effective potential antiepileptic drug in some forms of refractory epilepsy.

In an attempt to understand the mechanisms by which CBD exerts its anti-seizure effects, we investigated the effects of CBD at synaptic connections, and the intrinsic membrane properties of hippocampal CA1 pyramidal cells and two major inhibitory interneurons: fast spiking, parvalbumin -expressing (PV) and adapting, cholecystokinin-expressing (CCK) interneurons.

CONCLUSIONS & IMPLICATIONS:

In conclusion, our data suggest CBD restores excitability and morphological impairment in epileptic models to pre-epilepsy control levels through multiple mechanisms to restore normal network function.”

https://www.ncbi.nlm.nih.gov/pubmed/29574880

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.14202

Randomized, dose-ranging safety trial of cannabidiol in Dravet syndrome.

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“To evaluate the safety and preliminary pharmacokinetics of a pharmaceutical formulation of purified cannabidiol (CBD) in children with Dravet syndrome.

Exposure to CBD and its metabolites increased proportionally with dose. An interaction with N-CLB was observed, likely related to CBD inhibition of cytochrome P450 subtype 2C19. CBD resulted in more AEs than placebo but was generally well-tolerated.

CLASSIFICATION OF EVIDENCE:

This study provides Class I evidence that for children with Dravet syndrome, CBD resulted in more AEs than placebo but was generally well-tolerated.”

https://www.ncbi.nlm.nih.gov/pubmed/29540584

http://n.neurology.org/content/early/2018/03/14/WNL.0000000000005254

Anticonvulsive effects of endocannabinoids; an investigation to determine the role of regulatory components of endocannabinoid metabolism in the Pentylenetetrazol induced tonic- clonic seizures.

Metabolic Brain Disease

“2-Arachidonoylglycerol (2-AG) and anandamide are two major endocannabinoids produced, released and eliminated by metabolic pathways.

Anticonvulsive effect of 2-AG and CB1 receptor is well-established. Herein, we designed to investigate the anticonvulsive influence of key components of the 2-AG and anandamide metabolism.

It seems extracellular accumulation of 2-AG or anandamide has anticonvulsive effect through the CB1 receptor, while intracellular anandamide accumulation is proconvulsive through TRPV1.”

https://www.ncbi.nlm.nih.gov/pubmed/29504066

https://link.springer.com/article/10.1007%2Fs11011-018-0195-5

Cannabidiol for treatment of refractory childhood epilepsies: Experience from a single tertiary epilepsy center in Slovenia.

“Refractory epilepsies in children present a major burden for patients and their families. Cannabidiol (CBD) has been suggested as a potential treatment for refractory epilepsies. The aim of this study was to evaluate the effectiveness of add-on therapy with CBD for the treatment of refractory childhood epilepsies.

METHOD:

Patients with childhood-onset refractory epilepsy, treated at the tertiary epilepsy center of the University Children’s Hospital Ljubljana, Slovenia, were included in the study. Add-on therapy with CBD was initiated once the child’s epilepsy was categorized as pharmacoresistant to other antiepileptic drugs/therapies. The dosage of CBD was gradually increased to at least 8mg/kg/day. The effect of CBD treatment was evaluated by the reduction in seizure burden and presence of side effects (positive and negative). Serial electroencephalography was performed in some children.

RESULTS:

Sixty-six patients were included in the analysis. Thirty-two (48.5%) patients had a more than 50% improvement regarding seizure burden, 14 of whom (21.2%) became seizure-free. None of the patients reported worsening of seizure frequency, but CBD had no effect in 15 (22.7%) patients. Some patients reported less vigorous seizures, shorter duration of seizures, shorter time to recovery, and other positive side effects of CBD treatment. Adverse effects were reported in 5/66 children.

CONCLUSIONS:

In our cohort of patients, CBD was found to have potential benefits as add-on therapy for refractory childhood epilepsies, mainly by reducing seizure burden.”

https://www.ncbi.nlm.nih.gov/pubmed/29526578

http://www.epilepsybehavior.com/article/S1525-5050(17)30942-3/fulltext

Evidence for cannabis and cannabinoids for epilepsy: a systematic review of controlled and observational evidence.

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“Review evidence for cannabinoids as adjunctive treatments for treatment-resistant epilepsy.

Systematic search of Medline, Embase and PsycINFO was conducted in October 2017. Outcomes were: 50%+ seizure reduction, complete seizure freedom; improved quality of life (QoL).

Tolerability/safety were assessed by study withdrawals, adverse events (AEs) and serious adverse events (SAEs). Analyses were conducted in Stata V.15.0. 36 studies were identified: 6 randomised controlled trials (RCTs), 30 observational studies. Mean age of participants was 16.1 years (range 0.5-55 years).

Cannabidiol (CBD) 20 mg/kg/day was more effective than placebo at reducing seizure frequency by 50%+(relative risk (RR) 1.74, 95% CI 1.24 to 2.43, 2 RCTs, 291 patients, low Grades of Recommendation, Assessment, Development and Evaluation (GRADE) rating). The number needed to treat for one person using CBD to experience 50%+ seizure reduction was 8 (95% CI 6 to 17).

CBD was more effective than placebo at achieving complete seizure freedom (RR 6.17, 95% CI 1.50 to 25.32, 3 RCTs, 306 patients, low GRADE rating), and improving QoL (RR 1.73, 95% CI 1.33 to 2.26), however increased risk of AEs (RR 1.24, 95% CI 1.13 to 1.36) and SAEs (RR 2.55, 95% CI 1.48 to 4.38). Pooled across 17 observational studies, 48.5% (95% CI 39.0% to 58.1%) of patients reported 50%+ reductions in seizures; in 14 observational studies 8.5% (95% CI 3.8% to 14.5%) were seizure-free. Twelve observational studies reported improved QoL (55.8%, 95% CI 40.5 to 70.6); 50.6% (95% CI 31.7 to 69.4) AEs and 2.2% (95% CI 0 to 7.9) SAEs.

Pharmaceutical-grade CBD as adjuvant treatment in paediatric-onset drug-resistant epilepsy may reduce seizure frequency. Existing RCT evidence is mostly in paediatric samples with rare and severe epilepsy syndromes; RCTs examining other syndromes and cannabinoids are needed.”

https://www.ncbi.nlm.nih.gov/pubmed/29511052

http://jnnp.bmj.com/content/early/2018/02/05/jnnp-2017-317168

“Cannabis Compounds Reduce Epileptic Seizure Frequency In Children And Teenagers” http://www.iflscience.com/health-and-medicine/cannabis-compounds-reduce-epileptic-seizure-frequency-in-children-and-teenagers/

“Cannabis ingredient ‘reduces epilepsy seizures'”  https://www.webmd.boots.com/news/20180307/cannabis-ingredient-for-epilepsy-seizures

“Marijuana Derivative Successfully Treats Teen Epilepsy in New Experiments”  https://www.inverse.com/article/41985-cbd-marijuana-treat-seizures-epilepsy

Cannabidiol Regulates Long Term Potentiation Following Status Epilepticus: Mediation by Calcium Stores and Serotonin.

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“Epilepsy is a devastating disease, with cognitive and emotional consequences that are not curable.

In recent years, it became apparent that cannabinoids help patients to cope with epilepsy.

We have studied the effects of cannabidiol (CBD) on the ability to produce long term potentiation (LTP) in stratum radiatum of CA1 region of the mouse hippocampus.

Exposure to seizure-producing pilocarpine reduced the ability to generate LTP in the slice.

Pre-exposure to CBD prevented this effect of pilocarpine.

Furthermore, CBD caused a marked increase in ability to generate LTP, an effect that was blocked by calcium store antagonists as well as by a reduction in serotonin tone. Serotonin, possibly acting at a 5HT1A receptor, or fenfluramine (FFA), which causes release of serotonin from its native terminals, mimicked the effect of CBD.

It is proposed that CBD enhances non-NMDA LTP in the slice by facilitating release of serotonin from terminals, consequently ameliorating the detrimental effects of pilocarpine.”

Cannabis as an anticonvulsant

BMJ Journals“There are records of the cannabis plant being used for medicinal purposes in ancient times, and in the 19th century it was used as an effective anti-epileptic drug (AED) in children.

However, because of its abuse potential, most countries imposed laws restricting its cultivation and use, and this has greatly inhibited research into possible therapeutic uses.

Things are now changing, and cannabis derivatives are now used legally to treat, for example, pain, nausea and spasticity.

The plant contains over 100 biologically active compounds, and recently it has been possible to isolate these and identify the neurochemical mechanisms by which some of them operate: one in particular, cannabidiol”

https://www.ncbi.nlm.nih.gov/pubmed/29449212

http://adc.bmj.com/content/early/2018/02/15/archdischild-2018-314921

Cannabis for paediatric epilepsy: challenges and conundrums.

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“Research is expanding for the use of cannabidiol as an anticonvulsant drug. The mechanism of cannabidiol in paediatric epilepsy is unclear but is thought to play a role in modulation of synaptic transmission. Evidence for its efficacy in treating epilepsy is limited but growing, with a single pharmaceutical company-funded randomised double-blind controlled trial in children with Dravet syndrome. Progress towards the use of medicinal cannabinoids incorporates a complex interplay of social influences and political and legal reform. Access to unregistered but available cannabidiol in Australia outside of clinical trials and compassionate access schemes is state dependent and will require Therapeutic Goods Administration approval, although the cost may be prohibitive. Further clinical trials are needed to clearly define efficacy and safety, particularly long term.”

https://www.ncbi.nlm.nih.gov/pubmed/29438649

Efficacy of artisanal preparations of cannabidiol for the treatment of epilepsy: Practical experiences in a tertiary medical center.

“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.”

“In this retrospective study, we report that artisanal CBD is helpful in the treatment of medically refractory seizures.”

Cannabidiol for drug-resistant seizures in the Dravet syndrome

Journal of Paediatrics and Child Health

“Dravet syndrome (severe myoclonic epilepsy of infancy) is characterised by difficult-to-control seizures. Media reports and small clinical trials suggest that cannabidiol, a non-toxic extract of cannabis, can reduce seizure frequency. A recent multicentre randomised controlled trial of 120 children aged 2–18 years with Dravet syndrome supports its efficacy.

Over a 14-week period, children taking 20 mg/kg/day of cannabidiol had a 22.8% reduction (95% confidence interval 5.4–41.1) in seizure frequency compared to a 4-week baseline period. Median convulsive frequency fell from 12.4 to 5.9 per month on cannabidiol, while the placebo group had no change from baseline. No attempt was made to measure non-convulsive seizures (e.g. absences). Subjects took a median of three other anti-convulsant drugs during the trial. Adverse effects were common with cannabidiol, particularly somnolence, fatigue, loss of appetite, vomiting and diarrhoea. Eight patients in the cannabidiol group withdrew compared to one in the placebo group.

Nevertheless, 62% of caregivers in the cannabidiol group felt the patient’s overall condition had improved, using a validated global score, compared to 34% in the placebo group (P = 0.02). Unfortunately, the high rate of adverse events may have led to widespread loss of caregiver blinding, and the study is relatively short term. Nevertheless, the reduction in seizures is clinically relevant, and further longer-term randomised controlled trials are clearly warranted. ” https://www.ncbi.nlm.nih.gov/pubmed/29314377  http://onlinelibrary.wiley.com/doi/10.1111/jpc.13803/full