THC/CBD Spray Reduced Cancer Pain That Opioids Could Not Fully Control | Research

The takeaway

In 177 cancer patients with opioid-refractory pain, THC/CBD extract spray significantly reduced pain scores compared to placebo, with 43% of patients achieving at least 30% pain reduction versus 21% on placebo.

Read this if you or someone you know has cancer pain that opioids do not fully control.

43% of THC/CBD patients achieved 30%+ pain reduction vs 21% on placebo; THC alone was not significant

What the researchers found

One hundred seventy-seven cancer patients whose pain was inadequately controlled by opioids were randomized to THC/CBD extract spray (60 patients), THC-only extract spray (58 patients), or placebo (59 patients) for two weeks.

The THC/CBD group showed statistically significant pain improvement compared to placebo (mean change -1.37 vs -0.69 on a numerical rating scale). The THC-only group showed improvement (-1.01 vs -0.69) but did not reach significance.

Twice as many THC/CBD patients achieved clinically meaningful pain reduction (30% or more): 43% versus 21% on placebo. The THC-only group response rate (23%) was similar to placebo.

Opioid background medication doses did not change across groups, confirming the cannabinoid effect was additive rather than opioid-replacing.

One negative finding: THC/CBD worsened nausea and vomiting scores compared to placebo (p=0.02).

Why it matters

This was one of the strongest clinical trials supporting cannabinoids as adjunctive pain therapy in cancer patients already on opioids. The finding that THC/CBD was effective but THC alone was not highlighted the importance of CBD in the formulation.

The numbers in context

177 patients. THC/CBD pain reduction: -1.37 vs placebo -0.69 (significant). THC alone: -1.01 (not significant). 30% responders: THC/CBD 43% vs placebo 21% (significant). THC alone 23% (not significant). Nausea worsened with THC/CBD (p=0.02).

How the study worked

Multicenter, double-blind, randomized, placebo-controlled, parallel-group trial. 177 patients with advanced cancer pain inadequately controlled by chronic opioids. Two-week treatment with THC/CBD extract, THC extract, or placebo spray. Primary outcome: change in mean pain NRS score.

What this study cannot tell us

Two-week trial may not reflect long-term outcomes. The THC-only group's failure to reach significance raises questions about why CBD was necessary. Nausea worsening with THC/CBD is a significant concern. Open-label extension data were not reported in this paper.

How to read the evidence

Well-designed multicenter RCT with adequate sample size (177). Two-week duration and the nausea side effect are limitations.

When this study was published

Published in 2010. This trial was pivotal in the regulatory approval of Sativex for cancer pain in several countries.

The bigger picture

Cancer pain management remains inadequate for many patients despite opioid therapy. This trial showed that adding a THC/CBD spray could provide meaningful additional relief, supporting Sativex's later approval for cancer pain in some jurisdictions.

Questions still open

Why was THC/CBD effective but THC alone was not? Would longer treatment produce sustained benefit? Can the nausea side effect be managed? What is the optimal dosing for cancer pain?

Common questions

Why did the combination of THC and CBD work better than THC alone?

The mechanism is not fully clear from this trial, but CBD may enhance THC analgesic effects, reduce some THC side effects, or contribute its own pain-relieving properties. The finding reinforces that the combination is more than the sum of its parts for pain management.

Did patients stop needing opioids?

No. Opioid doses remained unchanged across all groups. The cannabinoid spray provided additional pain relief on top of existing opioid therapy, not as a replacement. This additive effect is clinically valuable for patients whose pain is not adequately controlled by opioids alone.

Read the original research

Multicenter, double-blind, randomized, placebo-controlled, parallel-group study of the efficacy, safety, and tolerability of THC:CBD extract and THC extract in patients with intractable cancer-related pain.

Journal of pain and symptom management, 39(2), 167-79

View on PubMed ↗Publisher’s paper ↗

Citation

Johnson, Jeremy R; Burnell-Nugent, Mary; Lossignol, Dominique; Ganae-Motan, Elena Doina; Potts, Richard; Fallon, Marie T. (2010). Multicenter, double-blind, randomized, placebo-controlled, parallel-group study of the efficacy, safety, and tolerability of THC:CBD extract and THC extract in patients with intractable cancer-related pain.. Journal of pain and symptom management, 39(2), 167-79. https://doi.org/10.1016/j.jpainsymman.2009.06.008