Prophylactic administration of cannabidiol reduces microglial inflammatory response to kainate-induced seizures and neurogenesis


“Microglia, the dynamic innate immune cells of the central nervous system, become activated in epilepsy. The process of microglial activation in epilepsy results in the creation of an inflammatory environment around the site of seizure onset, which contributes to the epileptogenic process and epilepsy progression. Cannabidiol (CBD) has been effective for use as an adjunctive treatment for two severe pediatric seizure disorders. Newly recognized as an Food and Drug Administration (FDA)-approved drug treatment in epilepsy, it has gained in popularity primarily for pain management. Although CBD is readily available in stores and online retailers, its mechanism of action and specifically its effects on microglia and their functions are yet fully understood. In this study, we examine the effects of commercially available CBD on microglia inflammatory activation and neurogenic response, in the presence and absence of seizures. We use systemic administration of kainate to elicit seizures in mice, which are assessed behaviorally. Artisanal CBD is given in different modes of administration and timing to dissect its effect on seizure intensity, microglial activation and aberrant seizure-related neurogenesis. CBD significantly dampens microglial migration and accumulation to the hippocampus. While long term artisanal CBD use does not prevent or lessen seizure severity, CBD is a promising adjunctive partner for its ability to depress epileptogenic processes. These studies indicate that artisanal CBD is beneficial as it both decreases inflammation in the CNS and reduces the number of ectopic neurons deposited in the hippocampal area post seizure.”

A nutraceutical product, extracted from Cannabis sativa, modulates voltage-gated sodium channel function

ISRCTN - Publish with BioMed Central

“Background: Purified cannabidiol (CBD), a non-psychoactive phytocannabinoid, has gained regulatory approval to treat intractable childhood epilepsies. Despite this, artisanal and commercial CBD-dominant hemp-based products continue to be used by epilepsy patients. Notably, the CBD doses used in these latter products are much lower than that found to be effective in reducing seizures in clinical trials with purified CBD. This might be because these CBD-dominant hemp products contain other bioactive compounds, including phytocannabinoids and terpenes, which may exert unique effects on epilepsy-relevant drug targets. Voltage-gated sodium (NaV) channels are vital for initiation of neuronal action potential propagation and genetic mutations in these channels result in epilepsy phenotypes. Recent studies suggest that NaV channels are inhibited by purified CBD. However, the effect of cannabis-based products on the function of NaV channels is unknown.

Methods: Using automated-planar patch-clamp technology, we profile a hemp-derived nutraceutical product (NP) against human NaV1.1-NaV1.8 expressed in mammalian cells to examine effects on the biophysical properties of channel conductance, steady-state fast inactivation and recovery from fast inactivation.

Results: NP modifies peak current amplitude of the NaV1.1-NaV1.7 subtypes and has variable effects on the biophysical properties for all channel subtypes tested. NP potently inhibits NaV channels revealing half-maximal inhibitory concentration (IC50) values of between 1.6 and 4.2 μg NP/mL. Purified CBD inhibits NaV1.1, NaV1.2, NaV1.6 and NaV1.7 to reveal IC50 values in the micromolar range. The CBD content of the product equates to IC50 values (93-245 nM), which are at least an order of magnitude lower than purified CBD. Unlike NP, hemp seed oil vehicle alone did not inhibit NaV channels, suggesting that the inhibitory effects of NP are independent of hemp seed oil.

Conclusions: This CBD-dominant NP potently inhibits NaV channels. Future study of the individual elements of NP, including phytocannabinoids and terpenes, may reveal a potent individual component or that its components interact to modulate NaV channels.”

Long-term cannabidiol treatment for seizures in patients with tuberous sclerosis complex: An open-label extension trial

“Objective: To evaluate the long-term safety and efficacy of add-on cannabidiol (CBD) in patients with seizures associated with tuberous sclerosis complex (TSC) in the open-label extension (OLE) of the randomized, placebo-controlled phase 3 trial GWPCARE6 (NCT02544763). Results of an interim (February 2019 data cut) analysis are reported.

Methods: Patients who completed the randomized trial enrolled to receive CBD (Epidiolex® in the United States; Epidyolex® in the EU; 100 mg/mL oral solution). The initial target dose was 25 mg/kg/day, which, based on response and tolerability, could be decreased or increased up to 50 mg/kg/day. The primary end point was safety. Key secondary end points included percentage reduction in TSC-associated (countable focal and generalized) seizures, responder rates, and Subject/Caregiver Global Impression of Change (S/CGIC).

Results: Of 201 patients who completed the randomized phase, 199 (99%) entered the OLE. Mean age was 13 years (range, 1-57). At the time of analysis, 5% of patients had completed treatment, 20% had withdrawn, and 75% were ongoing. One-year retention rate was 79%. Median treatment time was 267 days (range, 18-910) at a 27 mg/kg/day mean modal dose. Most patients (92%) had an adverse event (AE). Most common AEs were diarrhea (42%), seizure (22%), and decreased appetite (20%). AEs led to permanent discontinuation in 6% of patients. There was one death that was deemed treatment unrelated by the investigator. Elevated liver transaminases occurred in 17 patients (9%) patients; 12 were taking valproate. Median percentage reductions in seizure frequency (12-week windows across 48 weeks) were 54%-68%. Seizure responder rates (≥50%, ≥75%, 100% reduction) were 53%-61%, 29%-45%, and 6%-11% across 12-week windows for 48 weeks. Improvement on the S/CGIC scale was reported by 87% of patients/caregivers at 26 weeks.

Significance: In patients with TSC, long-term add-on CBD treatment was well tolerated and sustainably reduced seizures through 48 weeks, with most patients/caregivers reporting global improvement.”

“The results of our study show that add-on CBD can be an efficacious long-term treatment for TSC-associated seizures with manageable side effects and has been approved in patients as young as 1 year of age in the United States.”

Antiseizure Effects of Fully Characterized Non-Psychoactive Cannabis sativa L. Extracts in the Repeated 6-Hz Corneal Stimulation Test


“Compounds present in Cannabis sativa L. preparations have recently attracted much attention in the treatment of drug-resistant epilepsy. Here, we screened two olive oil extracts from a non-psychoactive C. sativa variety, fully characterized by high-performance liquid chromatography and gas chromatography. Particularly, hemp oils with different concentrations of terpenes were administered at the same dose of cannabidiol (25 mg/kg/day orally), 1 h before the 6-Hz corneal stimulation test (44 mA). Mice were stimulated once a day for 5 days and evaluated by video-electrocorticographic recordings and behavioral analysis. Neuronal activation was assessed by FosB/ΔFosB immunoreactivity. Both oils significantly reduced the percentage of mice experiencing convulsive seizures in comparison to olive oil-treated mice (p < 0.050; Fisher’s exact test), but only the oil enriched with terpenes (K2) significantly accelerated full recovery from the seizure. These effects occurred in the presence of reduced power of delta rhythm, and, instead, increased power of theta rhythm, along with a lower FosB/ΔFosB expression in the subiculum (p < 0.050; Duncan’s method). The overall findings suggest that both cannabinoids and terpenes in oil extracts should be considered as potential therapeutic agents against epileptic seizures and epilepsy.”

Long-term use of cannabidiol-enriched medical cannabis in a prospective cohort of children with drug-resistant developmental and epileptic encephalopathy

Epilepsy Action

“Objective: We report our findings regarding effectiveness, safety, and tolerability of cannabidiol (CBD)-enriched medical cannabis as add-on therapy in children with drug-resistant epileptic encephalopathies (DEEs) after a median follow-up of 20 months.

Methods: A prospective cohort study was conducted to assess effectiveness, safety, and tolerability of CBD-enriched medical cannabis oil added to standard antiseizure medications in children with drug-resistant DEE seen at a single center.

Results: Between October 2018 and March 2020, 59 patients were enrolled. Mean age at enrollment was 10.5 years (range, 2-17 years). Median treatment duration was 20 months (range, 12-32). Median age at first seizure was 8 months (range, 1 day – 10 years). At the end of follow-up, 78% of the children had a ≥ 50% decrease in seizure frequency and 47.5% had a > 75% decrease. Seven patients (11.9%) were seizure free. The number of seizures was reduced from a median of 305/month to 90/month, amounting to a mean reduction of 57% and a median reduction 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, intolerance to the drug, or poor compliance.

Conclusion: In children with drug-resistant DEEs, long-term treatment of CBD-enriched medical cannabis as an adjuvant therapy to antiseizure therapy was found to be safe, well tolerated, and effective. Sustained reductions in seizure frequency and improvement of aspects of daily living were observed compared to our preliminary findings.”

  • “•Long-term use of CBD-enriched medical cannabis as add-on treatment seems safe and effective in DEE.
  • The drug was well tolerated and had a positive impact on aspects of daily living.
  • Good results were found in patients with LGS and DS, as well as those with DEEs other than LGS and DS.
  • No tolerance to CBD-enriched medical cannabis was observed in any of the children.”

Effect of Cannabinoids on Electroencephalography of a Child with Lennox-Gastaut Syndrome

“Cannabinoids have been found to be effective in controlling seizures and the highly purified form of cannabinoid derived for Cannabis sativa . Cannabidiol (CBD) is now approved for Lennox-Gastaut syndrome (LGS) and Dravet syndrome. CBD was used in a 9-year-old boy with LGS (unknown etiology) with very good results. The electroencephalography (EEG) response was very dramatic with near normalization of EEG background and complete control of seizures. The effect of CBD on EEG with such an improvement has not been described previously. Also, this adds to evidence that early intervention in LGS with CBD might be more helpful and improve outcomes.”

Cannabidiol interactions with voltage-gated sodium channels

eLife logo “Voltage-gated sodium channels are targets for a range of pharmaceutical drugs developed for treatment of neurological diseases.

Cannabidiol (CBD), the non-psychoactive compound isolated from cannabis plants, was recently approved for treatment of two types of epilepsy associated with sodium channel mutations.

This study used high resolution X-ray crystallography to demonstrate the detailed nature of the interactions between CBD and the NavMs voltage-gated sodium channel, and electrophysiology to show the functional effects of binding CBD to these channels.

CBD binds at a novel site at the interface of the fenestrations and the central hydrophobic cavity of the channel. Binding at this site blocks the transmembrane-spanning sodium ion translocation pathway, providing a molecular mechanism for channel inhibition. Modelling studies suggest why the closely-related psychoactive compound tetrahydrocannabinol may not have the same effects on these channels. Finally, comparisons are made with the TRPV2 channel, also recently proposed as a target site for CBD.

In summary, this study provides novel insight into a possible mechanism for CBD interactions with sodium channels.”

Practical use of pharmaceutically purified oral cannabidiol in Dravet syndrome and Lennox-Gastaut syndrome

Publication Cover “Pharmaceutically purified oral cannabidiol (CBD) has been recently approved by the US Food and Drug Administration and European Medicines Agency as treatment of seizures associated with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS), which are severe and difficult-to-treat developmental and epileptic encephalopathies with onset in early childhood.

Areas covered: This review will critically review the pharmacokinetic properties of CBD, the interactions with antiseizure and non-antiseizure medications, and the main tolerability and safety issues to provide guidance for its use in everyday practice.

Expert opinion: CBD is metabolized in the liver and can influence the activity of enzymes involved in drug metabolism. The best characterized drug-drug interaction is between CBD and clobazam. The most common adverse events include somnolence, gastrointestinal discomfort and increase in serum transaminases.

High-grade purified CBD oral solution represents an effective therapeutic option in patients with DS and LGS.

The findings cannot be extrapolated to other cannabis-based products, synthetic cannabinoids for medicinal use and non-medicinal cannabis and CBD derivatives.”

“Pharmaceutically purified oral cannabidiol (CBD) is approved for treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome.”

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 US (in 2018) and as Epidyolex in the EU (in 2019) as the first cannabis-derived therapeutic for the treatment for 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.”

Clinical implications of trials investigating drug-drug interactions between cannabidiol and enzyme inducers or inhibitors or common antiseizure drugs

“Highly purified cannabidiol (CBD) has demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut syndrome or Dravet syndrome in randomized, double-blind, add-on, controlled phase 3 trials.

It is important to consider the possibility of drug-drug interactions (DDIs). Here, we review six trials of CBD (Epidiolex/Epidyolex; 100 mg/mL oral solution) in healthy volunteers or patients with epilepsy, which investigated potential interactions between CBD and enzymes involved in drug metabolism of common antiseizure drugs (ASDs).

CBD did not affect CYP3A4 activity. Induction of CYP3A4 and CYP2C19 led to small reductions in exposure to CBD and its major metabolites. Inhibition of CYP3A4 activity did not affect CBD exposure and caused small increases in exposure to CBD metabolites. Inhibition of CYP2C19 activity led to a small increase in exposure to CBD and small decreases in exposure to CBD metabolites.

One potentially clinically important DDI was identified: combination of CBD and clobazam (CLB) did not affect CBD or CLB exposure, but increased exposure to major metabolites of both compounds. Reduction of CLB dose may be considered if adverse reactions known to occur with CLB are experienced when it is coadministered with CBD.

There was a small increase of exposure to stiripentol (STP) when coadministered with CBD. STP had no effect on CBD exposure but led to minor decreases in exposure to CBD metabolites. Combination of CBD and valproate (VPA) did not cause clinically important changes in the pharmacokinetics of either drug, or 2-propyl-4-pentenoic acid. Concomitant VPA caused small increases in exposure to CBD metabolites. Dose adjustments are not likely to be necessary when CBD is combined with STP or VPA.

The safety results from these trials were consistent with the known safety profile of CBD. These trials indicate an overall low potential for DDIs between CBD and other ASDs, except for CLB.”