“Cannabidiol (CBD), a non-euphoric component of cannabis, reduces seizures in multiple forms of pediatric epilepsies, but the mechanism(s) of anti-seizure action remain unclear. In one leading model, CBD acts at glutamatergic axon terminals, blocking the pro-excitatory actions of an endogenous membrane phospholipid, lysophosphatidylinositol (LPI), at the G-protein-coupled receptor GPR55. However, the impact of LPI-GPR55 signaling at inhibitory synapses and in epileptogenesis remains underexplored. We found that LPI transiently increased hippocampal CA3-CA1 excitatory presynaptic release probability and evoked synaptic strength in WT mice, while attenuating inhibitory postsynaptic strength by decreasing GABA_ARγ₂ and gephyrin puncta. LPI effects at excitatory and inhibitory synapses were eliminated by CBD pre-treatment and absent after GPR55 deletion. Acute pentylenetrazole-induced seizures elevated GPR55 and LPI levels, and chronic lithium-pilocarpine-induced epileptogenesis potentiated LPI’s pro-excitatory effects. We propose that CBD exerts potential anti-seizure effects by blocking LPI’s synaptic effects and dampening hyperexcitability.”

https://pubmed.ncbi.nlm.nih.gov/36787750/

https://www.cell.com/neuron/fulltext/S0896-6273(23)00066-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0896627323000661%3Fshowall%3Dtrue

“Objective: Cannabidiol (CBD) is approved for treatment of Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC). Several studies suggest anti-seizure effects also beyond these three epilepsy syndromes.

Methods: In a retrospective multi-center study, we analyzed the efficacy and tolerability of CBD in patients with epilepsy at 16 epilepsy centers.

Results: The study cohort comprised 311 patients with epilepsy with a median age of 11.3 (0-72) years (235 children and adolescents, 76 adults). Therapy with CBD was off-label in 91.3% of cases due to age, epilepsy subtype, lack of adjunct therapy with clobazam, and/or higher dose applied. CBD titration regimens were slower than recommended, with good tolerability of higher doses particularly in children. Of all patients, 36.9% experienced a reduction in seizure frequency of >50%, independent of their epilepsy subtype or clobazam co-medication. The median observation period was 15.8 months. About one third of all patients discontinued therapy within the observation period due to adverse effects or lack of efficacy. Adverse effects were reported frequently (46.9%).

Significance: Our study highlights that CBD has an anti-seizure effect comparable to other anti-seizure medications with a positive safety profile independent of the epilepsy subtype. Comedication with clobazam was not associated with a better outcome. Higher doses to achieve seizure frequency reduction were safe, particularly in children. These findings call for further trials for an extended approval of CBD for other epilepsy subtypes and for children < 2 years of age.”

https://pubmed.ncbi.nlm.nih.gov/36693811/

https://onlinelibrary.wiley.com/doi/10.1002/epi4.12699

“Objective: Cannabidiol (CBD) expanded access program (EAP), initiated in 2014, provided add-on CBD to patients with treatment-resistant epilepsy (TRE) at 35 US epilepsy centers. Prior publications reported results through December 2016; herein, we present efficacy and safety results through January 2019.

Methods: Patients received plant-derived highly purified CBD (Epidiolex®; 100 mg/mL oral solution), increasing from 2-10 mg/kg/d to tolerance or maximum 25-50 mg/kg/d dose, depending on the study site. Efficacy endpoints included percentage change from baseline in median monthly convulsive and total seizure frequency and ≥50%, ≥75%, and 100% responder rates across 12-week visit windows for up to 192 weeks. Adverse events (AEs) were documented at each visit.

Results: Of 892 patients in the safety analysis set, 322 (36%) withdrew; lack of efficacy (19%) and AEs (7%) were the most commonly reported primary reasons for withdrawal. Median (range) age was 11.8 years (0-74.5), and patients were taking a median (range) 3 (0-10) antiseizure medications (ASMs) at baseline; most common ASMs were clobazam (47%), levetiracetam (34%), and valproate (28%). Median top CBD dose was 25 mg/kg/d; median exposure duration was 694 days. Median percentage reduction from baseline ranged from 50%-67% for convulsive seizures and 46%-66% for total seizures. Convulsive seizure responder rates (≥50%, ≥75%, and 100% reduction) ranged from 51%-59%, 33%-42%, and 11%-17% of patients across visit windows, respectively. AEs were reported in 88% of patients and serious AEs in 41%; 8% withdrew because of an AE. There were 20 deaths during the study deemed unrelated to treatment by the investigator. Most common AEs (≥20% of patients) were diarrhea (33%), seizure (24%), and somnolence (23%).

Significance: Add-on CBD was associated with sustained seizure reduction up to 192 weeks with an acceptable safety profile and can be used for long-term treatment of TREs.”

https://pubmed.ncbi.nlm.nih.gov/36537757/

https://onlinelibrary.wiley.com/doi/10.1111/epi.17496

“Objective: The objective of this systematic review with meta-analysis was to evaluate the efficacy, safety, and short- and long-term tolerability of cannabidiol (CBD), as an adjunct treatment, in children and adults with Dravet syndrome (SD), Lennox-Gataut syndrome (LGS), or tuberous sclerosis complex (TSC), with inadequate control of seizures.

Methods: This systematic review was conducted through a search for scientific evidence in the Mediline/PubMed, Central Cochrane, and ClinicalTrials.gov databases until April 2022. Selected randomized clinical trials (RCTs) that presented the outcomes: reduction in the frequency of seizures and total seizures (all types), number of patients with a response greater than or equal to 50%, change in caregiver global impression of change (CGIC) (improvement ≥1 category on the initial scale), adverse events (AEs), and tolerability to treatment. This review followed Preferred Reporting Items for Systematic reviews and Meta-Analyses.

Results: Notably, six RCTs were included, with a total of 1,034 patients with SD, LGS, and TSC, of which 3 were open-label extension RCTs. The meta-analysis of the studies showed that the use of CBD as compared with placebo, in patients with convulsive seizures refractory to the use of medications, reduces the frequency of seizures by 33%; increases the number of patients with a reduction ≥50% in the frequency of seizures by 20%; increases the number of patients with absence of seizures by 3%; improves the clinical impression evaluated by the caregiver or patient (S/CGIC) in 21%; increases total AEs by 12%; increases serious AE by 16%; increases the risk of treatment abandonment by 12%; and increases the number of patients with transaminase elevation (≥3 times the referral) by 15%.

Conclusions: This systematic review, with meta-analysis, supports the use of CBD in the treatment of patients with seizures, originated in DS, LGS, and TSC, who are resistant to the common medications, presenting satisfactory benefits in reducing seizures and tolerable toxicity.”

https://pubmed.ncbi.nlm.nih.gov/36417631/

https://www.scielo.br/j/ramb/a/vh3QpdBkQfXVrdw7nT63bdd/?lang=en

“Objective: To summarize and evaluate clinical experiences with refractory status epilepticus in which cannabidiol (CBD) was utilized for cessation of seizure activity.

Methods: A comprehensive literature review was performed on PubMED, MEDLINE, Scopus, and CINAHL between May – June 2022 with the assistance of a medical reference librarian using the following search terms: “Cannabidiol” [MAJR], “Status Epilepticus” [MAJR], “New-Onset Refractory Status Epilepticus”, and “cannabidiol.” Reports that provided dosing regimens and patient outcomes were included.

Results: Thirty-two articles were screened. Five articles were selected for inclusion in this review and detailed the clinical courses of 11 patients. Five of the 11 patients received CBD during the chronic epilepsy stage, while the remaining 6 received it during a period of acute status epilepticus. Patients were trialed on an average of 9 anti-epileptic drugs prior to CBD administration, after which 9 of the 11 patients experienced a reduction of seizure activity. Dosing of CBD ranged between 5-25 mg/kg/day and was titrated based on patient response to therapy. Adverse effects were relatively benign and were generally limited to gastrointestinal discomfort, reported after seizure cessation.

Conclusions: CBD may provide a potentially efficacious and safe management strategy in refractory status epilepticus, including patients with new-onset refractory status epilepticus and febrile infection-related epilepsy syndrome. A potential for drug-drug interactions between CBD and anti-epileptic drugs warrants judicious monitoring. Additional research is necessary to determine a definitive dosing strategy for this agent.”

https://pubmed.ncbi.nlm.nih.gov/36399869/

“The efficacy and safety of CBD has been demonstrated in Lennox-Gastaut and Darvet Syndromes.”

https://www.seizure-journal.com/article/S1059-1311(22)00260-6/fulltext

“Introduction: Cannabidiol (CBD) has been clinically approved for intractable epilepsies, offering hope that novel anticonvulsants in the phytocannabinoid class might be developed. Looking beyond CBD, we have recently reported that a series of biosynthetic precursor molecules found in cannabis display anticonvulsant properties. However, information on the pharmacological activities of these compounds on CNS drug targets is limited. The current study aimed to fill this knowledge gap by investigating whether anticonvulsant phytocannabinoids affect T-type calcium channels, which are known to modulate neuronal excitability, and may be relevant to the anti-seizure effects of this class of compounds. 

Materials and methods: A fluorescence-based assay was used to screen the ability of the phytocannabinoids to inhibit human T-type calcium channels overexpressed in HEK-293 cells. A subset of compounds was further examined using patch-clamp electrophysiology. Alphascreen technology was used to characterise selected compounds against G-protein coupled-receptor 55 (GPR55) overexpressed in HEK-293 cells, as GPR55 is another target of the phytocannabinoids. 

Results: A single 10 µM concentration screen in the fluorescence-based assay showed that phytocannabinoids inhibited T-type channels with substantial effects on Ca_v3.1 and Ca_v3.2 channels compared to the Ca_v3.3 channel. The anticonvulsant phytocannabinoids cannabigerovarinic acid (CBGVA) and cannabidivarinic acid (CBDVA) had the greatest magnitudes of effect (≥80% inhibition against Ca_v3.1 and Ca_v3.2), so were fully characterized in concentration-response studies. CBGVA and CBDVA had IC₅₀ values of 6 μM and 2 µM on Ca_v3.1 channels; 2 μM and 11 µM on Ca_v3.2 channels, respectively. Biophysical studies at Ca_v3.1 showed that CBGVA caused a hyperpolarisation shift of steady-state inhibition. Both CBGVA and CBDVA had a use-dependent effect and preferentially inhibited Ca_v3.1 current in a slow inactivated state. CBGVA and CBDVA were also shown to antagonise GPR55. 

Conclusion and implications: These findings show that CBGVA and CBDVA inhibit T-type calcium channels and GPR55. These compounds should be further investigated to develop novel therapeutics for treating diseases associated with dysfunctional T-type channel activity.”

https://pubmed.ncbi.nlm.nih.gov/36386164/

“Here we report that the understudied minor phytocannabinoids CBDVA and CBGVA, which are biosynthetic precursor molecules found in the cannabis plant, inhibit both T-type calcium channels and GPR55 receptors in vitro. Our data suggest that these compounds could be further explored for therapeutic potential in disease states which involve these channels or receptors, such as epilepsy, insomnia, pain and gastrointestinal disorders.”

https://www.frontiersin.org/articles/10.3389/fphar.2022.1048259/full