Prescription CBD Without Clobazam Reduced Seizures in 30% of Lennox-Gastaut Patients at 12 Months

In a real-world European study, plant-derived CBD (Epidyolex) used without the commonly co-prescribed drug clobazam achieved a 50%+ seizure reduction in 30% of Lennox-Gastaut patients and 13% of Dravet patients at 12 months, with good retention and tolerability.

Nabbout, Rima et al.·Seizure·2023·Moderate EvidenceRetrospective Cohort
RTHC-04805Retrospective CohortModerate Evidence2023RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Retrospective Cohort
Evidence
Moderate Evidence
Sample
N=107

What This Study Found

Among 107 patients (92 LGS, 15 DS) receiving CBD without clobazam for at least 3 months, median seizure frequency change ranged from -6.2% to -20.9% for LGS and 0% to -16.7% for DS over 3-month intervals. At 12 months, 30% of LGS and 13% of DS patients achieved 50%+ seizure reduction. Retention on CBD without clobazam was 63% at 12 months. Adverse events occurred in 31%, mostly somnolence, seizure, diarrhea, and decreased appetite.

Key Numbers

107 patients (92 LGS, 15 DS). Mean CBD dose: 13.54 mg/kg/day (LGS), 11.56 mg/kg/day (DS). 50%+ seizure reduction at 12 months: 30% LGS, 13% DS. 12-month retention: 63%. Adverse events: 31%. Four patients had elevated liver enzymes.

How They Did This

Retrospective chart review of patients aged 2+ with LGS or DS enrolled in a European Early Access Program for plant-derived CBD (Epidyolex). Data covered 3 months before through 12 months after CBD initiation. Only patients not taking clobazam were included.

Why This Research Matters

Most clinical trials of CBD for epilepsy included clobazam, raising questions about whether CBD works independently. This real-world study provides evidence that CBD without clobazam still provides meaningful seizure reduction for some patients with severe epilepsy syndromes.

The Bigger Picture

CBD has been approved for LGS and DS primarily based on trials where many patients also took clobazam. Because clobazam and CBD interact (CBD raises clobazam levels), there has been debate about how much of the benefit comes from CBD alone. This study, while uncontrolled, helps fill that gap.

What This Study Doesn't Tell Us

No placebo control or randomization. Retrospective chart review with potential for incomplete documentation. Small DS subgroup (n = 15). Open-label design introduces expectation bias. Mean CBD dose was below the upper end of the approved dose range.

Questions This Raises

  • ?Would higher CBD doses without clobazam produce better seizure control?
  • ?Why is the response rate lower in Dravet syndrome than Lennox-Gastaut when CBD is used without clobazam?

Trust & Context

Key Stat:
30% of LGS patients achieved 50%+ seizure reduction with CBD alone at 12 months
Evidence Grade:
Real-world chart review from a structured access program, providing practical effectiveness data but lacking placebo control.
Study Age:
Published 2023, data from European Early Access Program.
Original Title:
Retrospective chart review study of use of cannabidiol (CBD) independent of concomitant clobazam use in patients with Lennox-Gastaut syndrome or Dravet syndrome.
Published In:
Seizure, 110, 78-85 (2023)
Database ID:
RTHC-04805

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Looks back at existing records to find patterns.

What do these levels mean? →

Frequently Asked Questions

Does CBD work for seizures without clobazam?

This study suggests it can. About 30% of Lennox-Gastaut patients achieved meaningful seizure reduction with CBD alone at 12 months, and 63% stayed on it for a full year.

What side effects were seen?

Adverse events occurred in 31% of patients, most commonly somnolence, seizure recurrence, diarrhea, and decreased appetite. Four patients had elevated liver enzymes.

Read More on RethinkTHC

Cite This Study

RTHC-04805·https://rethinkthc.com/research/RTHC-04805

APA

Nabbout, Rima; Arzimanoglou, Alexis; Auvin, Stéphane; Berquin, Patrick; Desurkar, Archana; Fuller, Douglas; Nortvedt, Charlotte; Pulitano, Patrizia; Rosati, Anna; Soto, Victor; Villanueva, Vicente; Cross, J Helen. (2023). Retrospective chart review study of use of cannabidiol (CBD) independent of concomitant clobazam use in patients with Lennox-Gastaut syndrome or Dravet syndrome.. Seizure, 110, 78-85. https://doi.org/10.1016/j.seizure.2023.05.003

MLA

Nabbout, Rima, et al. "Retrospective chart review study of use of cannabidiol (CBD) independent of concomitant clobazam use in patients with Lennox-Gastaut syndrome or Dravet syndrome.." Seizure, 2023. https://doi.org/10.1016/j.seizure.2023.05.003

RethinkTHC

RethinkTHC Research Database. "Retrospective chart review study of use of cannabidiol (CBD)..." RTHC-04805. Retrieved from https://rethinkthc.com/research/nabbout-2023-retrospective-chart-review-study

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.