Cannabis Extract for Post-Surgical Pain: Clear Dose-Response But Trial Stopped Over Safety Concern
A dose-escalation trial of oral cannabis extract for post-operative pain found significant dose-related reductions in rescue analgesia needs (100% at 5mg, 50% at 10mg, 25% at 15mg), but the study was terminated after a serious vasovagal event at the highest dose.
Quick Facts
What This Study Found
Patients were given a single dose of 5, 10, or 15 mg of oral cannabis extract (Cannador) for post-operative pain after stopping patient-controlled analgesia. The dose-response relationship was clear and significant.
All 11 patients (100%) receiving 5 mg requested rescue analgesia. At 10 mg, 15 of 30 patients (50%) needed rescue medication. At 15 mg, only 6 of 24 patients (25%) needed rescue (log rank test for trend P < 0.001). The number needed to treat to prevent one rescue request was 2.0 for 10 mg and 1.3 for 15 mg, comparable to many routinely used analgesics.
However, there were significant trends for increasing sedation (P = 0.03) and more adverse events (P = 0.002) at higher doses. The study was terminated after a serious vasovagal adverse event in a patient receiving the 15 mg dose.
Key Numbers
5 mg: 100% needed rescue (11/11). 10 mg: 50% needed rescue (15/30). 15 mg: 25% needed rescue (6/24). Trend: P < 0.001. NNT to prevent rescue: 2.0 (10 mg), 1.3 (15 mg). Increasing sedation: P = 0.03. More adverse events: P = 0.002. Study terminated: serious vasovagal event at 15 mg.
How They Did This
Multi-center dose-escalation study. Patients aged 18-75 received a single dose of 5, 10, or 15 mg Cannador after stopping patient-controlled analgesia for at least moderate pain. Dose escalation based on rescue analgesia requests and adverse effects. Pain relief, pain intensity, and side effects recorded over 6 hours.
Why This Research Matters
The clear dose-response relationship and competitive number needed to treat values provided strong evidence for cannabinoid analgesic efficacy. However, the safety-related termination highlights the challenge of finding the right dose: effective pain relief required doses that also produced more adverse events.
The Bigger Picture
This trial demonstrated that cannabis-based analgesics can be effective but face the same dose-limiting side effect challenge as many other pain medications. The NNT values were comparable to established analgesics, suggesting cannabinoids could be competitive if safety margins can be improved.
What This Study Doesn't Tell Us
Study terminated early due to adverse event, limiting the total evidence base. Single-dose design cannot assess effects of repeated dosing. The dose-escalation design means treatment groups were not concurrent. The vasovagal event may or may not have been drug-related.
Questions This Raises
- ?Can the analgesic dose be separated from the adverse event dose through different formulations or delivery methods?
- ?How do these cannabinoid NNT values compare to the specific analgesics these patients would otherwise receive?
Trust & Context
- Key Stat:
- Rescue analgesia needed by 100% at 5mg, 50% at 10mg, 25% at 15mg (P < 0.001 trend)
- Evidence Grade:
- Randomized dose-escalation trial published in Anesthesiology. Clear dose-response but terminated early due to safety concerns, limiting conclusions about the optimal therapeutic window.
- Study Age:
- Published in 2006 in Anesthesiology. Cannabis-based analgesic research has continued, with more emphasis on non-oral delivery methods and combination products.
- Original Title:
- A multicenter dose-escalation study of the analgesic and adverse effects of an oral cannabis extract (Cannador) for postoperative pain management.
- Published In:
- Anesthesiology, 104(5), 1040-6 (2006)
- Authors:
- Holdcroft, Anita(2), Maze, Mervyn, Doré, Caroline, Tebbs, Susan, Thompson, Simon
- Database ID:
- RTHC-00229
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Can cannabis extract relieve post-surgical pain?
This trial showed clear dose-related pain relief: at the 15 mg dose, only 25% of patients needed additional pain medication, compared to 100% at 5 mg. The number needed to treat was comparable to many standard analgesics. However, higher doses also produced more sedation and adverse events.
Why was the trial stopped?
The study was terminated after a patient receiving the 15 mg dose experienced a serious vasovagal event (a sudden drop in heart rate and blood pressure). While it is unclear if this was definitively drug-related, the safety concern warranted stopping the trial.
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Cite This Study
https://rethinkthc.com/research/RTHC-00229APA
Holdcroft, Anita; Maze, Mervyn; Doré, Caroline; Tebbs, Susan; Thompson, Simon. (2006). A multicenter dose-escalation study of the analgesic and adverse effects of an oral cannabis extract (Cannador) for postoperative pain management.. Anesthesiology, 104(5), 1040-6.
MLA
Holdcroft, Anita, et al. "A multicenter dose-escalation study of the analgesic and adverse effects of an oral cannabis extract (Cannador) for postoperative pain management.." Anesthesiology, 2006.
RethinkTHC
RethinkTHC Research Database. "A multicenter dose-escalation study of the analgesic and adv..." RTHC-00229. Retrieved from https://rethinkthc.com/research/holdcroft-2006-a-multicenter-doseescalation-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.