Adding THC to Opioids Does Not Improve Knee Arthritis Pain
What Researchers Found About Arthritis and Cannabis
The Study at a Glance
Published
Neuropsychopharmacology, 2023
Researchers
Multiple institutions (USA)
Study Type
Randomized Controlled TrialParticipants
37 patients · Acute (single session per condition)
Key Finding
The present study shows minimal benefit of combining dronabinol (10 mg) and hydromorphone (4 mg) for analgesia and improving physical functioning in adults with knee osteoarthritis.
Key Finding: The present study shows minimal benefit of combining dronabinol (10 mg) and hydromorphone (4 mg) for analgesia and improving physical functioning in adults with knee osteoarthritis.
What Researchers Studied About Arthritis and Cannabis
This study evaluated whether combining a cannabinoid (dronabinol/THC) with an opioid (hydromorphone) provides better pain relief than either alone in people with knee osteoarthritis.
This was the first study to evaluate this combination in patients with chronic pain.
Outcomes included clinical pain, experimentally-induced pain, physical and cognitive function, subjective drug effects, and human abuse potential.
How This Randomized Controlled Trial Was Conducted
This was a within-subject (crossover), double-blind, randomized, placebo-controlled study.
37 participants (65% women; mean age 62) with knee osteoarthritis and at least 3/10 pain intensity were included.
Each participant received all 4 conditions: 1. Placebo + Placebo 2. Hydromorphone (4 mg) + Placebo 3. Dronabinol (10 mg) + Placebo 4. Hydromorphone (4 mg) + Dronabinol (10 mg)
Arthritis Treatment Results
The Main Results:
- 1NO significant analgesic effects on clinical pain severity across ALL drug conditions
- 2NO improvement in physical functioning across ALL drug conditions
- 3LITTLE enhancement of hydromorphone analgesia by dronabinol on evoked pain
- 4Subjective drug effects and some abuse potential ratings increased in combo
- 5BUT abuse potential was NOT higher than dronabinol alone
- 6NO serious adverse events reported
- 7Hydromorphone produced more MILD adverse events than placebo
- 8Hydromorphone + dronabinol produced more MODERATE adverse events than either alone
- 9ONLY hydromorphone impaired cognitive performance (not dronabinol)
By the Numbers
| Statistic | What It Means |
|---|---|
| 37 patients | Adults with knee osteoarthritis (65% women, mean age 62) |
| No significant effect | Neither drug nor combination reduced clinical pain severity |
| 4 mg + 10 mg | Hydromorphone and dronabinol doses tested |
| More moderate AEs | Combination produced more moderate adverse events than either alone |
Adults with knee osteoarthritis (65% women, mean age 62)
Neither drug nor combination reduced clinical pain severity
Hydromorphone and dronabinol doses tested
Combination produced more moderate adverse events than either alone
What This Means for Arthritis Patients
If you have knee arthritis and were hoping to combine cannabis with opioids for better pain relief, this study has disappointing results.
Neither dronabinol alone, hydromorphone alone, nor the combination reduced clinical pain significantly compared to placebo.
Adding THC to opioids did not make the opioid work better. There was little enhancement of pain relief.
Safety concerns: The combination produced more moderate adverse events than either drug alone. This means combining them may increase side effects without providing additional benefit.
One positive finding: Only the opioid (not dronabinol) impaired cognitive function.
The researchers conclude there is "minimal benefit" from combining these medications for knee osteoarthritis.
Quick Answers: Arthritis and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
Do cannabis and opioids work better together for pain?
No, based on this RCT. In 37 knee osteoarthritis patients, combining dronabinol (10 mg) with hydromorphone (4 mg) did not significantly improve pain vs placebo. Little enhancement of opioid analgesia by THC was observed.
Source: Campbell et al., Neuropsychopharmacology, 2023 (PMID: 37202479)
Does THC help knee osteoarthritis pain?
No significant effect was found. A 2023 RCT in 37 patients found dronabinol (10 mg THC) did not significantly reduce clinical pain severity or improve physical functioning in knee osteoarthritis compared to placebo.
Source: Campbell et al., Neuropsychopharmacology, 2023 (PMID: 37202479)
What happens if I combine marijuana with opioids?
More side effects, no added benefit. A 2023 RCT found combining dronabinol + hydromorphone produced more moderate adverse events than either alone. The combination provided no additional pain relief for knee arthritis.
Source: Campbell et al., Neuropsychopharmacology, 2023 (PMID: 37202479)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Acute dosing only (single session)
- Specific doses tested (4 mg hydromorphone, 10 mg dronabinol)
- Knee osteoarthritis only
- Small sample (37 patients)
- Laboratory setting may not reflect real-world use
The Bottom Line on Cannabis for Arthritis
This RCT of 37 knee osteoarthritis patients found NO significant pain relief from dronabinol (THC), hydromorphone (opioid), or the combination vs placebo. Adding THC to opioids did not enhance analgesia but did increase moderate adverse events. Conclusion: minimal benefit from combining cannabinoids with opioids for osteoarthritis.
Do You Qualify for Medical Marijuana?
If you're living with Arthritis, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
Condition Research
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Source
Campbell CM, Mun CJ, Hamilton KR, et al. "Within-subject, double-blind, randomized, placebo-controlled evaluation of combining the cannabinoid dronabinol and the opioid hydromorphone in adults with chronic pain" Neuropsychopharmacology. 2023. DOI: 10.1038/s41386-023-01597-1
Important Information
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 25, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
Copyright & Fair Use
Research summaries are provided under fair use (17 U.S.C. § 107) for educational purposes. We provide brief summaries with attribution, not full reproductions. All studies remain the intellectual property of their respective authors and publishers.
Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
For complete information, see our Terms of Use and Research Content Policy.
FAQs: Cannabis for Arthritis
Does adding cannabis to opioids improve pain relief?
Not in this study. A 2023 RCT found combining dronabinol (THC) with hydromorphone did NOT significantly improve clinical pain in knee osteoarthritis patients compared to either drug alone or placebo.
Is it safe to combine cannabis with opioids?
No serious adverse events, but more moderate side effects. The combination produced more moderate adverse events than either drug alone. Combining them may increase side effects without providing additional benefit.
Can cannabis help me reduce my opioid dose for arthritis?
No, research does not support this. Dronabinol (THC) alone showed no significant pain relief for knee osteoarthritis, and adding it to opioids did not enhance analgesia.