The efficacy of cannabidiol for seizures reduction in pharmacoresistant epilepsy: a systematic review and meta-analysis

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“Background: Epilepsy is a neurological syndrome caused by excessive neuronal discharges, with a part of the patients being pharmacoresistant to the traditional treatment. Cannabidiol, a non-psychoactive component of Cannabis Sativa, shows promise as an alternative, but further research is needed to quantify its efficacy.

Methods: This literature systematic review was made following the PRISMA protocol guidelines. The Google Scholar, Scielo, and PubMed/MEDLINE databases were included using the descriptors “Cannabidiol”, “Epilepsy”, and “Drug Resistant Epilepsy”. This research was registered in the Prospero platform with the identification (CRD42024479643).

Results: A total of 1448 results were identified from the PubMed, Virtual Health Library, and Google Scholar databases. After applying exclusion criteria, six studies met the criteria for full-text evaluation and eligibility. The compiled analysis showed that the patients who received cannabidiol experienced a 41.0875% reduction in the total number of seizures, compared to an average reduction of 18.1% in placebo groups. This represents a 127% higher response rate for patients who received the intervention.

Conclusions: Given these results, it is possible to conclude that the therapeutic response of cannabidiol is worthy of consideration in new protocols and of being added to public healthcare systems for its antiepileptic potential. However, the high efficacy rate observed in the placebo group suggests that other methods of data collection analysis may be employed.”

https://pubmed.ncbi.nlm.nih.gov/40217555/

“Based on the results from the analyzed studies, it can be concluded that the addition of CBD to the treatment regimen for patients with pharmacoresistant epilepsy is beneficial in most cases. The doses of 10 mg/kg/day and 20 mg/kg/day were compared in 5 out of 6 studies, with a higher dose demonstrating superior seizure control. However, the lower dose also showed significant efficacy, making it a viable option for inclusion in treatment and guidelines as well.”

https://aepi.biomedcentral.com/articles/10.1186/s42494-024-00191-2

Optimization of seizure prevention by cannabidiol (CBD)

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“Objective: Cannabidiol (CBD) is one of the most prominent non-psychotropic cannabinoids with known therapeutic potentials. Based on its anti-seizure efficacy, the first cannabis derived pharmaceutical grade CBD-based medication was approved in the USA in 2018 for the treatment of seizures in patients 2 years and older. Despite the effectiveness in reducing seizures, there remain several major questions on the optimization of CBD therapy for epilepsy such as the optimal dosage, composition, and route of delivery, which are the main objective of this current study.

Methods: We evaluated the antiseizure effects of CBD through different compositions, routes of delivery, and dosages in a pre-clinical model. We used a kainic acid-induced epilepsy model in C57BL/6 mice, treated them with placebo and/or CBD through inhalation, oral, and injection (intraperitoneal) routes. We used CBD broad spectrum (inhaled and intraperitoneal) vs CBD isolate formulations. We employed the Racine scaling system to evaluate the severity of the seizures, flow cytometry for measuring immune biomarkers and neurotrophic factors, and histologic analysis to examine and compare the groups.

Results: Our findings showed that all forms of CBD reduced seizures severity. Among the combination of CBD tested, CBD broad spectrum via inhalation was the most effective in the treatment of epileptic seizures (p < 0.05) compared to other forms of CBD treatments.

Conclusion: Our data suggest that route and CBD formulations affect its efficacy in the prevention of epileptic seizures. Inhaled broad spectrum CBD showed a potential superior effect compared to other delivery routes and CBD formulations in the prevention of epileptic seizures, which warrants further research.”

https://pubmed.ncbi.nlm.nih.gov/40177581/

https://www.degruyterbrill.com/document/doi/10.1515/tnsci-2022-0362/html

[Real-life study with pharmaceutical cannabidiol in refractory epilepsy]

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“Pharmaceutical-grade cannabidiol (CBD) is an alternative treatment for patients with drug-resistant epilepsy (DRE). In 2022, the Italian Hospital of Buenos Aires implemented a non-medical change (NMC) of treatment, replacing one commercial pharmaceutical-grade CBD product with another, the latter also being the initial option for new patients.

Our objective was to evaluate the clinical outcomes of the commercial product change in this population.

Methods: Retrospective cohort of DRE patients who either switched from one commercial pharmaceutical-grade CBD product to another or started treatment with the new product. The clinical response was evaluated by changes in seizure frequency, perception of change with the Patient Global Impression of Change (PGIC) scale, and safety considering discontinuation and/or the presence of adverse effects.

Results: Nineteen patients were included, 12 in the change group and 7 in the new start group (7 pediatric and 12 adults). One patient discontinued treatment due to lack of response. Among those who completed follow-up, 8 (44%) reduced seizure frequency, 6 (33%) showed no change, and 4 (22%) increased seizure frequency. According to the PGIC scale, 9 (50%) remained unchanged, 5 (28%) reported barely noticeable changes, and 4 (22%) reported improvement. Adverse events were mild and transient.

Conclusion: The new commercial pharmaceutical-grade CBD product is a safe and valid option both for substitution and initial treatment in patients with DRE. During the treatment period, patients perceived stability or improvement according to the PGIC scale.”

https://pubmed.ncbi.nlm.nih.gov/40163830/

Antiepileptic activity and potential mechanism of full-spectrum hemp extract

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“Epilepsy is the fourth most common neuropsychiatric disorder. Although the approval of Epidiolex has ignited hope for patients, there is still a large gap in the field of anti-seizure research. The effect and underlying mechanism of full-spectrum hemp extract (HE) remains unclear.

Here this study investigated the anti-seizure effect of HE on seizure models. The results showed that HE significantly reduced seizure susceptibility and prolonged seizure latency with better pharmacokinetic performance compared to CBD.

This article then further explored the anti-seizure active components and their possible mechanism in HE. The results indicated that cannabichromene (CBC) and cannabinol (CBN) were involved in the anti-seizure process, especially CBC showed a strong allosteric enhancement effects on CBD binding site of the GABAA receptor, which implied that the GABAA receptor seemed to be the primary anti-epileptic target of HE.

This article not only presents the great potential of HE as a candidate for new anti-epileptic drugs with less psychoactive, but also provides a valuable contribution to subsequent mechanism research and drug development on epilepsy.”

https://pubmed.ncbi.nlm.nih.gov/40166106/

https://www.sciencedirect.com/science/article/pii/S2667325824004552?via%3Dihub

Expanding the therapeutic role of highly purified cannabidiol in monogenic epilepsies: A multicenter real-world study

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“Objective: This real-world, retrospective, multicenter study aims to investigate the effectiveness of highly purified cannabidiol (CBD) in a large cohort of patients with epilepsy of genetic etiology due to an identified monogenic cause. Additionally, we examine the potential relationship between specific genetic subgroups and treatment response.

Methods: This study was conducted across 27 epilepsy centers and included patients with monogenic epileptic disorders (pathogenic or likely pathogenic variants) who were treated with highly purified CBD for at least 3 months.

Results: A total of 266 patients (135 females, 50.8%) with monogenic epilepsies were included with a median age at CBD initiation of 12 years (interquartile range [IQR] = 7-19) and a median follow-up duration of 17 months (IQR = 12-24). Overall, 77 different monogenic epilepsies have been included, with the most common genes being SCN1A (32.3%), TSC2 (13.5%), CDKL5, and MECP2 (4.5% each). The mean seizure reduction at the last follow-up was 38.6%, with 47.5% of patients achieving ≥50% seizure reduction and 7.4% achieving seizure freedom. The Clinical Global Impression scale indicated improvement in 65.8% of patients. The general linear mixed model revealed that a shorter maximum duration of seizure freedom before CBD initiation and a higher degree of intellectual disability were independently associated with lower CBD effectiveness. Conversely, no significant differences in seizure outcome were observed across different epilepsy syndromes (Lennox-Gastaut syndrome, Dravet syndrome, tuberous sclerosis complex epilepsy, and other developmental and epileptic encephalopathy), between approved indications and off-label use, or between concomitant clobazam use or not.

Significance: This study supports CBD as a potential treatment for monogenic epilepsies beyond its licensed indications, demonstrating comparable effectiveness between approved and off-label use and suggesting genetic subgroups with promising treatment responses.”

https://pubmed.ncbi.nlm.nih.gov/40126049/

Value of cannabidiol as adjunctive treatment for Lennox Gastaut syndrome: cost-effectiveness and budget impact analysis

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“Background: Lennox-Gastaut syndrome (LGS) is a severe encephalopathic disease that leads to a decrease in the quality of life, physical injury, psychosocial impairment, and a significant increase in treatment costs. Cannabidiol (CBD) is approved for the adjunctive treatment of tonic-colonic seizures in LGS. This study aimed to determine the cost-effectiveness of CBD compared to the usual treatment in patients with LGS syndrome.

Methods: We developed a lifetime-horizon Markov model to compare the cost-effectiveness of adjunctive CBD versus usual care. Additionally, we performed a budget impact analysis over a 5-year time horizon. The findings were presented as the incremental cost-effectiveness ratio (ICER) for CEA, with a willingness to pay threshold of $18,261 per QALY gained, and as the difference in the overall budget ($) between the scenarios with and without CBD for budget impact assessment.

Results: In the base case scenario, CBD was cost-effective compared with usual care $6573 per QALY. Sensitivity analyses substantiated these results. From a healthcare perspective, there is a 77% probability that CBD is cost-effective at a willingness to pay of $18,261 per quality-adjusted life-year (QALY). Overall, the market access of CBD was associated to an increased budget of about $3,459,846 (+ 33%) in the next 5 years simulated.

Conclusions: Compared to usual care, CBD seems to be cost-effective in LGS patients and sustainable, with less than 34% overall budget increased in the next 5 years. Future studies need to confirm our results in the real word setting and in other countries.”

https://pubmed.ncbi.nlm.nih.gov/40038638/

“Our study demonstrates that CBD is valuable as an add-on therapy for patients with LGS in Iran. At current list prices in Iran and assuming a WTP threshold of $18,261/QALY, CBD is cost-effective for the treatment of LGS. So CBD has a more advantage of efficacy compared with usual care and its incremental BI for health system is relatively acceptable. The present study also provides a reference for stakeholders to judge the value of cannabidiol.”

https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-025-03972-9

The use of cannabidiol in patients with Lennox-Gastaut syndrome and Dravet syndrome in the UK Early Access Program: A retrospective chart review study

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“Purpose: To evaluate clinical outcomes from the UK Early Access Program in patients aged 2-17 years with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) treated with plant-derived highly purified cannabidiol (CBD; Epidyolex®; 100 mg/mL oral solution).

Methods: Retrospective chart review of data collected from baseline (1 month before CBD treatment initiation) until 12 months’ treatment, CBD discontinuation, death, or loss to follow up.

Results: At baseline, all 26 patients enrolled (LGS, n = 17; DS, n = 9; male, 73 %; mean [range] age, 11.8 [3.0-17.0] years) experienced motor seizures; 92 % were taking ≥ 1 antiseizure medication. Median (IQR) CBD dosage at 6 months (6 M; n = 12) was 6.0 (2.7) mg/kg/day, and 12 months (12 M; n = 9) 7.3 (2.1) mg/kg/day. Median (IQR) percentage change from baseline for motor seizures was – 56.7 % (60.7) at 6 M (n = 20), and – 60.0 % (53.3) at 12 M (n = 15). Patients experiencing ≥ 50 % and ≥ 75 % reduction in motor seizures were 13/20 (65 %) and 5/20 (25 %) at 6 M, respectively, and 10/15 (67 %) and 6/15 (40 %) at 12 M, respectively. Mean (SD) motor seizure-free days/month were 1.5 (4.3) at baseline (n = 24, missing data n = 2), 2.4 (6.3) at 6 M (n = 18), and 2.7 (5.5) at 12 M (n = 15). At 12 M, CBD retention for patients with follow-up data was 14/19 (74 %), whilst 7/26 (27 %) were lost to follow up. The number of patients reporting ≥ 1 adverse event of special interest (most common: gastrointestinal) was 14/20 (70 %) and 8/15 (53 %) at 6 M and 12 M, respectively.

Conclusion: Results demonstrate a reduction in motor seizures and a safety profile consistent with previous studies.”

https://pubmed.ncbi.nlm.nih.gov/39898301/

“Results on CBD effectiveness and safety are consistent with previous studies.”

https://www.sciencedirect.com/science/article/pii/S2589986424000881?via%3Dihub

First case report of effective and safe application of cannabidiol to treat concurrent ALG3-CDG and Lennox-Gastaut Syndrome

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“This study presents the first reported case of a Korean patient with Alpha-1,3-Mannosyltransferase-Congenital Disorder of Glycosylation (ALG3-CDG), characterized by a novel maternally inherited missense mutation and a previously reported paternally inherited nonsense mutation. The patient exhibited typical ALG3-CDG manifestations, including developmental delays, epilepsy, and multisystem involvement, alongside a diagnosis of Lennox-Gastaut Syndrome (LGS).

Cannabidiol therapy, combined with dietary management, led to seizure freedom for over 13 months, significant EEG improvement, and enhanced developmental outcomes.

This case underscores the potential of cannabidiol as a promising treatment strategy for patients with ALG3-CDG and refractory epilepsy, broadening therapeutic perspectives for this rare disorder.”

https://pubmed.ncbi.nlm.nih.gov/39831946/

https://link.springer.com/article/10.1007/s10072-025-08004-1

Update on Cannabidiol in Drug-Resistant Epilepsy

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“Cannabidiol (CBD) has arisen as a promising therapeutic option for children with drug-resistant epilepsy (DRE). CBD has received regulatory nod from different regulatory authorities in the United States, Europe, and India for children with DRE particularly, Dravet syndrome (DS), Lennox Gastaut syndrome (LGS), and Tuberous sclerosis complex (TSC).

Recent clinical trials and observational studies highlight the potential of CBD to lower seizure frequency and provide better quality of life in children affected by these disorders.

The safety profile is generally favorable with minor common adverse events such as somnolence, diarrhea, and gastrointestinal issues. Furthermore, the expense associated with CBD remains a notable concern, especially in low- and middle-income countries such as India, where access to this promising treatment may be constrained. This draws attention to the cost-effective perspective of CBD.

This review aims to explore the pharmacological properties of CBD, its mechanisms of action, and the clinical evidence supporting its use in various pediatric epilepsies, including LGS, DS, and TSC. Additionally, this review sheds light on the current regulatory landscape in India where CBD use is still in its nascent stages, and discusses the challenges and opportunities for integrating CBD into clinical practice.”

https://pubmed.ncbi.nlm.nih.gov/39585547/

https://link.springer.com/article/10.1007/s12098-024-05337-1

Cannabidiol Treatment for Adult Patients with Drug-Resistant Epilepsies: A Real-World Study in a Tertiary Center

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“Background and purpose: Around 30% of patients with epilepsy show drug-resistant epilepsy (DRE). While cannabidiol has demonstrated efficacy as an adjunctive treatment in Dravet syndrome (DS), Lennox-Gastaut Syndrome (LGS), and epilepsy related to tuberous sclerosis complex (TSC), its more global effectiveness in adult patients with DRE apart from these three specific contexts needs to be clarified.

Methods: We conducted a retrospective study at the epilepsy unit of Pitié Salpêtrière Hospital. Patients initiating pharmaceutical cannabidiol treatment and followed for at least 1 year were included. Patients were categorized into “authorized” (LGS, DS, or TSC) and “off-label” groups. Cannabidiol effectiveness and tolerance were compared between groups, and characteristics of responders (patients with >50% reduction in seizure frequency) in the off-label group were examined.

Results: Ninety-one patients, followed by a median duration of 24 months, were included. A total of 35.2% of the patients were in the authorized group. No significant differences were observed in responder rates between groups (31.3% vs. 35.6%, p = 0.85) and retention rates at 1 year (75.0% vs. 74.6%, p = 0.97). Sleepiness was more commonly reported in the authorized group (50.0% vs. 22.0%, p = 0.01), with no other significant differences. Among off-label patients (n = 59), clobazam co-prescription was more prevalent in responders (71.4% vs. 28.9%, p = 0.002).

Conclusion: Our findings suggest that cannabidiol may benefit all adult patients with DRE, particularly those already receiving clobazam. Randomized controlled trials are warranted in off-label patients to validate these observational findings.”

https://pubmed.ncbi.nlm.nih.gov/39501537/

https://onlinelibrary.wiley.com/doi/10.1002/brb3.70122