Purified CBD reduced seizures in Dravet and Lennox-Gastaut syndromes and received FDA approval
A comprehensive review found that highly purified CBD (Epidiolex) significantly reduced seizures in randomized trials for Dravet syndrome and Lennox-Gastaut syndrome, earned FDA approval, and identified important drug interactions with clobazam and valproate.
Quick Facts
What This Study Found
This review compiled all available evidence on cannabis-derived treatments for epilepsy, from artisanal products through FDA-approved purified CBD.
While artisanal CBD products showed high rates of reported seizure improvement in surveys and retrospective studies, these lacked controlled dosing and rigorous design.
The stronger evidence came from open-label expanded access programs (EAPs) and randomized controlled trials of highly purified CBD (Epidiolex). The EAPs showed significant seizure frequency improvement across various treatment-resistant epilepsy types. The RCTs demonstrated significant seizure reduction compared to placebo specifically in Dravet syndrome and Lennox-Gastaut syndrome.
Important safety findings: the most common side effects were diarrhea and sedation, with sedation much more common in patients also taking clobazam. Liver enzyme elevations occurred, particularly in patients also taking valproate. CBD significantly increases levels of N-desmethylclobazam (clobazam's active metabolite) through CYP2C19 inhibition. Other possible interactions were identified with rufinamide, zonisamide, topiramate, and eslicarbazepine.
Key Numbers
RCTs showed significant seizure reduction vs. placebo in Dravet and Lennox-Gastaut syndromes. Most common side effects: diarrhea and sedation. CBD inhibits CYP2C19, increasing N-desmethylclobazam levels. Possible interactions with rufinamide, zonisamide, topiramate, eslicarbazepine.
How They Did This
Comprehensive review of published evidence on CBD for epilepsy, including artisanal product surveys, open-label expanded access programs, randomized placebo-controlled trials, and pharmacokinetic interaction studies.
Why This Research Matters
This review documents the journey from anecdotal reports to FDA approval for CBD in epilepsy, one of the most significant developments in cannabinoid medicine. The detailed drug interaction data is critical for clinicians managing patients on multiple anti-epileptic drugs.
The Bigger Picture
The CBD-for-epilepsy story represents the most successful translation of cannabinoid research into approved medicine. It demonstrates that rigorous clinical trials can validate cannabinoid therapeutics, and it highlights the importance of understanding drug interactions in patients taking multiple medications.
What This Study Doesn't Tell Us
Much of the artisanal product evidence comes from surveys and uncontrolled studies. The RCTs focused on two specific epilepsy syndromes and may not generalize to all epilepsy types. Long-term safety data was still accumulating at the time of publication. The review does not cover THC-containing preparations in detail.
Questions This Raises
- ?Will CBD prove effective for epilepsy types beyond Dravet and Lennox-Gastaut syndromes?
- ?Could specific ratios of CBD to THC provide additional therapeutic benefit for seizure control?
- ?How should clinicians manage the CBD-clobazam interaction in practice?
Trust & Context
- Key Stat:
- Purified CBD earned FDA approval for Dravet and Lennox-Gastaut epilepsy syndromes
- Evidence Grade:
- This review covers randomized controlled trials that led to FDA approval, representing strong evidence for CBD in these specific epilepsy syndromes.
- Study Age:
- Published in 2018, shortly after FDA approval of Epidiolex. Post-marketing data and additional indications have since emerged.
- Original Title:
- Cannabis for the Treatment of Epilepsy: an Update.
- Published In:
- Current neurology and neuroscience reports, 18(11), 73 (2018)
- Authors:
- Gaston, Tyler E, Szaflarski, Jerzy P(6)
- Database ID:
- RTHC-01659
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is CBD approved for epilepsy?
Yes. Highly purified CBD (Epidiolex) received FDA approval for Dravet syndrome and Lennox-Gastaut syndrome based on randomized controlled trials showing significant seizure reduction compared to placebo.
Does CBD interact with other seizure medications?
Yes. CBD significantly increases levels of clobazam's active metabolite through CYP2C19 inhibition, increasing sedation risk. Liver enzyme elevations are more common when CBD is taken with valproate. Possible interactions also exist with rufinamide, zonisamide, topiramate, and eslicarbazepine.
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Cite This Study
https://rethinkthc.com/research/RTHC-01659APA
Gaston, Tyler E; Szaflarski, Jerzy P. (2018). Cannabis for the Treatment of Epilepsy: an Update.. Current neurology and neuroscience reports, 18(11), 73. https://doi.org/10.1007/s11910-018-0882-y
MLA
Gaston, Tyler E, et al. "Cannabis for the Treatment of Epilepsy: an Update.." Current neurology and neuroscience reports, 2018. https://doi.org/10.1007/s11910-018-0882-y
RethinkTHC
RethinkTHC Research Database. "Cannabis for the Treatment of Epilepsy: an Update." RTHC-01659. Retrieved from https://rethinkthc.com/research/gaston-2018-cannabis-for-the-treatment
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.