A CBD/THC cannabis oil reduced seizures by 70.6% in children with Dravet syndrome in an open-label trial
A prospective open-label trial of 20 children with Dravet syndrome treated with a CBD-dominant cannabis oil (100 mg/mL CBD, 2 mg/mL THC) found a median motor seizure reduction of 70.6%, a 50% responder rate of 63%, significant EEG improvement, and improved quality of life over 20 weeks.
Quick Facts
What This Study Found
Twenty children with Dravet syndrome received add-on therapy with TIL-TC150, a cannabis oil containing 100 mg/mL CBD and 2 mg/mL THC.
Doses ranged from 2-16 mg/kg/day of CBD (mean achieved: 13.3 mg/kg/day) and 0.04-0.32 mg/kg/day of THC (mean: 0.27 mg/kg/day).
Nineteen of 20 participants completed the 20-week intervention.
Results showed a median motor seizure reduction of 70.6%, with 63% of patients achieving at least 50% seizure reduction.
There was a statistically significant improvement in quality of life and reduction in EEG spike activity.
Adverse events during titration included somnolence, anorexia, and diarrhea. Liver enzyme and platelet abnormalities were observed in patients also taking valproic acid.
The study provided the first safety and dosing data for THC-containing cannabis preparations in Dravet syndrome, complementing the pure CBD (Epidiolex) trial data.
Key Numbers
20 children, 19 completed 20 weeks. Mean CBD dose: 13.3 mg/kg/day (range 7-16). Mean THC dose: 0.27 mg/kg/day (range 0.14-0.32). Median motor seizure reduction: 70.6%. 50% responder rate: 63%. Significant QOL improvement and EEG spike reduction.
How They Did This
Prospective open-label trial. 20 children with Dravet syndrome. TIL-TC150 (Tilray cannabis oil: 100 mg/mL CBD, 2 mg/mL THC) as add-on therapy for 20 weeks. Monitored for seizure frequency, EEG changes, quality of life, and adverse events.
Why This Research Matters
While pure CBD (Epidiolex) trials have established CBD for Dravet syndrome, this study adds evidence that a CBD-dominant oil containing small amounts of THC is also safe and effective, with a notably high 70.6% median seizure reduction that compares favorably to pure CBD trial results.
The Bigger Picture
The inclusion of low-dose THC alongside CBD is notable because the entourage effect theory suggests whole-plant extracts may work differently than pure isolates. The high response rate in this open-label trial supports further investigation of CBD/THC combination products for severe epilepsy.
What This Study Doesn't Tell Us
Open-label design without placebo control, so true drug effect is uncertain. Small sample of 20 patients. Adverse events overlapped with those of concomitant medications (particularly valproic acid). 20-week duration may not capture long-term tolerance or adverse effects.
Questions This Raises
- ?Does the low-dose THC component contribute to efficacy beyond CBD alone?
- ?Would a randomized comparison of CBD/THC oil versus pure CBD show differences?
- ?Are the liver enzyme changes from the cannabis oil, valproic acid interaction, or both?
Trust & Context
- Key Stat:
- 70.6% median motor seizure reduction with 63% responder rate
- Evidence Grade:
- Moderate. Prospective design with multiple outcome measures, but open-label without placebo control limits certainty about true drug effect.
- Study Age:
- Published in 2018. CBD-based epilepsy treatments have since gained wider approval and clinical use.
- Original Title:
- A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.
- Published In:
- Annals of clinical and translational neurology, 5(9), 1077-1088 (2018)
- Authors:
- McCoy, Bláthnaid(4), Wang, Laura, Zak, Maria, Al-Mehmadi, Sameer, Kabir, Nadia, Alhadid, Kenda, McDonald, Kyla, Zhang, Grace, Sharma, Rohit, Whitney, Robyn, Sinopoli, Katia, Snead, O Carter
- Database ID:
- RTHC-01755
Evidence Hierarchy
A small preliminary study to test whether a larger study is feasible.
What do these levels mean? →Frequently Asked Questions
How does this compare to pure CBD (Epidiolex) trials?
The 70.6% median seizure reduction and 63% responder rate in this open-label study compare favorably to the ~39-40% reductions seen in randomized Epidiolex trials. However, open-label studies typically show larger effects than placebo-controlled trials due to expectation effects, so direct comparison is not straightforward.
Why include THC in a treatment for children?
The THC dose was very low (0.27 mg/kg/day on average, about 50 times less than the CBD dose). Some researchers believe small amounts of THC may enhance CBD's therapeutic effects through the entourage effect. The study monitored carefully for THC-related adverse effects.
Read More on RethinkTHC
- CBD-oil-quality-guide
- anxiety-medication-after-quitting-weed
- cannabis-chemotherapy-nausea
- cannabis-chronic-pain-research
- cannabis-epilepsy-CBD-Epidiolex
- cbd-anxiety-research-evidence
- cbd-for-weed-withdrawal
- cbd-vs-thc-difference
- medical-benefits-of-cannabis
- quitting-weed-before-surgery
- quitting-weed-medication-interactions
- quitting-weed-pregnancy
- quitting-weed-pregnant
- seniors-older-adults-cannabis-risks-medications
- weed-breastfeeding-THC-breast-milk
Cite This Study
https://rethinkthc.com/research/RTHC-01755APA
McCoy, Bláthnaid; Wang, Laura; Zak, Maria; Al-Mehmadi, Sameer; Kabir, Nadia; Alhadid, Kenda; McDonald, Kyla; Zhang, Grace; Sharma, Rohit; Whitney, Robyn; Sinopoli, Katia; Snead, O Carter. (2018). A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.. Annals of clinical and translational neurology, 5(9), 1077-1088. https://doi.org/10.1002/acn3.621
MLA
McCoy, Bláthnaid, et al. "A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.." Annals of clinical and translational neurology, 2018. https://doi.org/10.1002/acn3.621
RethinkTHC
RethinkTHC Research Database. "A prospective open-label trial of a CBD/THC cannabis oil in ..." RTHC-01755. Retrieved from https://rethinkthc.com/research/mccoy-2018-a-prospective-openlabel-trial
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.