CBD side effects: mostly mild, but dangerous when combined with certain epilepsy drugs
CBD is generally well-tolerated with mild side effects like sleepiness and diarrhea, but can cause severe, life-threatening reactions when combined with valproate or clobazam, two drugs commonly used in the epilepsy patients who take CBD.
Quick Facts
What This Study Found
Short-term CBD side effects are generally transitory, dose-dependent, and mild to moderate: somnolence, decreased appetite, and diarrhea. However, severe life-threatening reactions can occur, often related to uncontrolled combinations with valproate (hepatotoxicity risk) or clobazam (excessive sedation). These are widely used in Dravet and Lennox-Gastaut patients who are the target population for CBD.
Key Numbers
No specific incidence rates. Review noted dose-dependent effects and identified valproate and clobazam as primary interaction risks.
How They Did This
Brief review summarizing available data on short-term adverse events from clinical trials that led to Epidiolex FDA approval.
Why This Research Matters
The very patients most likely to benefit from CBD (those with severe epilepsy) are also taking the drugs most likely to cause dangerous interactions with CBD, making monitoring essential.
The Bigger Picture
The interaction concern highlights a broader issue: CBD is often perceived as universally safe because it is "natural," but it has real pharmacological interactions that can be serious.
What This Study Doesn't Tell Us
Brief review focused on short-term effects. Long-term safety data are lacking. Based primarily on clinical trial populations.
Questions This Raises
- ?What is the long-term safety profile of CBD in children?
- ?Can dosing adjustments of valproate and clobazam eliminate the interaction risk?
Trust & Context
- Key Stat:
- Life-threatening reactions possible with valproate or clobazam
- Evidence Grade:
- Based on clinical trial data from FDA approval process, the strongest available evidence.
- Study Age:
- 2020 review.
- Original Title:
- Adverse effects of cannabinoids.
- Published In:
- Epileptic disorders : international epilepsy journal with videotape, 22(S1), 29-32 (2020)
- Authors:
- Anciones, Carla, Gil-Nagel, Antonio(2)
- Database ID:
- RTHC-02385
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is CBD safe?
CBD is generally well-tolerated with mild side effects, but can cause severe reactions when combined with valproate (liver damage risk) or clobazam (excessive sedation), drugs commonly used in epilepsy patients.
What are the side effects of CBD?
Common side effects include sleepiness, decreased appetite, and diarrhea. These are typically dose-dependent and transitory. Serious effects occur mainly through drug interactions.
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Cite This Study
https://rethinkthc.com/research/RTHC-02385APA
Anciones, Carla; Gil-Nagel, Antonio. (2020). Adverse effects of cannabinoids.. Epileptic disorders : international epilepsy journal with videotape, 22(S1), 29-32. https://doi.org/10.1684/epd.2019.1125
MLA
Anciones, Carla, et al. "Adverse effects of cannabinoids.." Epileptic disorders : international epilepsy journal with videotape, 2020. https://doi.org/10.1684/epd.2019.1125
RethinkTHC
RethinkTHC Research Database. "Adverse effects of cannabinoids." RTHC-02385. Retrieved from https://rethinkthc.com/research/anciones-2020-adverse-effects-of-cannabinoids
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.