Cannabis-Based Medicines for MS Have Mild Side Effects But Raise Concerns for Psychosis-Prone and Pregnant Patients
Clinical trial data showed cannabis-based MS medicines had generally mild side effects (dry mouth, dizziness, somnolence), but the review urged caution for people predisposed to psychosis and pregnant women, and noted therapeutic benefits were still modest.
Quick Facts
What This Study Found
This review assessed the safety profile of cannabis-based medicinal extracts (CBMEs) for MS treatment. Clinical trial data showed adverse effects were generally mild: dry mouth, dizziness, somnolence, nausea, and intoxication. No cases of toxicity developed.
Despite evidence that cannabinoids can disrupt cognitive function and promote depression in recreational users, these adverse effects appeared unlikely with CBMEs based on available data. Effects on balance, motor control, and immune function also appeared clinically insignificant.
However, the review identified two populations warranting concern: people predisposed to psychosis, given growing evidence of cannabis-psychosis links, and pregnant women, given increasing evidence of adverse fetal effects. The author concluded that given the modest therapeutic benefits demonstrated so far and the risk of unknown long-term effects, caution was warranted.
Key Numbers
Common adverse effects: dry mouth, dizziness, somnolence, nausea, intoxication. No toxicity in any trial. Most trials ran only months long. Specific concerns: psychosis-predisposed individuals and pregnant women.
How They Did This
Safety review of clinical trial data on cannabis-based medicinal extracts for MS. Evaluated adverse effect profiles, cognitive impacts, effects on balance and motor control, immune function, psychosis risk, and reproductive safety.
Why This Research Matters
This review provided an honest assessment of both the safety and the limitations of cannabis-based MS medicines. The identification of specific at-risk populations (psychosis-prone individuals and pregnant women) helped guide clinical decision-making about who should and should not use these treatments.
The Bigger Picture
The cautious tone of this review, noting modest benefits and unknown long-term risks, contrasts with more enthusiastic assessments of cannabis-based medicines. This balanced perspective influenced regulatory decisions about labeling and prescribing guidelines for products like Sativex.
What This Study Doesn't Tell Us
Most clinical trials were relatively short (months), limiting knowledge of long-term safety. The review noted that unknown adverse effects could develop with longer use. The assessment of psychosis and pregnancy risks drew partly from recreational cannabis research, which may not directly apply to pharmaceutical preparations.
Questions This Raises
- ?Do the long-term safety profiles of cannabis-based medicines differ from those of recreational cannabis?
- ?At what level of psychosis predisposition should cannabis-based medicines be contraindicated?
Trust & Context
- Key Stat:
- Side effects generally mild (dry mouth, dizziness) but caution urged for psychosis-prone and pregnant patients
- Evidence Grade:
- Safety review synthesizing clinical trial data. Limited by the short duration of most trials and the difficulty of extrapolating long-term risks from short-term data.
- Study Age:
- Published in 2005. Long-term safety data from post-marketing surveillance of Sativex has since become available, providing a clearer safety picture.
- Original Title:
- The safety of cannabinoids for the treatment of multiple sclerosis.
- Published In:
- Expert opinion on drug safety, 4(3), 443-56 (2005)
- Authors:
- Smith, Paul F(5)
- Database ID:
- RTHC-00206
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Are cannabis-based MS medicines safe?
Short-term clinical trial data showed generally mild side effects. However, this review noted that most trials lasted only months, potential long-term effects were unknown, and specific caution was warranted for people predisposed to psychosis and for pregnant women.
Who should avoid cannabis-based medicines?
The review specifically identified two groups warranting concern: people predisposed to psychosis (given evidence linking cannabis to psychotic episodes) and pregnant women (given evidence of adverse effects on fetal development).
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Cite This Study
https://rethinkthc.com/research/RTHC-00206APA
Smith, Paul F. (2005). The safety of cannabinoids for the treatment of multiple sclerosis.. Expert opinion on drug safety, 4(3), 443-56.
MLA
Smith, Paul F. "The safety of cannabinoids for the treatment of multiple sclerosis.." Expert opinion on drug safety, 2005.
RethinkTHC
RethinkTHC Research Database. "The safety of cannabinoids for the treatment of multiple scl..." RTHC-00206. Retrieved from https://rethinkthc.com/research/smith-2005-the-safety-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.