Two Nabiximols Allodynia Trials Gave Different Average Pain Results
The nabiximols pain review describes an encouraging earlier allodynia trial followed by a larger trial without a statistically significant average pain advantage. The earlier positive result was not uniform confirmation across studies.
The earlier study favored the spray
In a trial of 125 patients with peripheral neuropathic pain characterized by allodynia, the review reports mean pain-score reductions of 1.48 points with THC:CBD spray and 0.52 with placebo. The between-group comparison was significant, with p = 0.004. Other measures, including forms of evoked allodynia and pain-related disability, also favored active treatment in that study.
The larger trial did not repeat every result
For a subsequent trial, the review’s evidence table reports an average pain advantage of 0.34 points versus placebo with p = 0.139. That mean-score comparison did not reach statistical significance. The studies also differed in duration and their analyzed populations. The two findings should therefore be described as mixed trial evidence, rather than treated as one replicated estimate of a fixed benefit.
Allodynia does not guarantee a treatment response
Allodynia describes pain provoked by stimuli that ordinarily would not be painful. It identifies a clinical feature, not a demonstrated biological rule that every affected patient responds to cannabinoids. Differences in baseline conditions, outcomes, attrition and other treatment may influence trial results, but the review does not establish one explanation for their divergence. A fair account reports the positive earlier study and the later nonsignificant mean comparison together. These human pain findings also do not establish that a symptom response predicts normal attention, motor performance or safety in other activities; those are separate outcomes.
Related analysis: the broader findings and limitations of this research.
Research cited
The study observations discussed here are reported in the supplied review: Überall (2020). A Review of Scientific Evidence for THC:CBD Oromucosal Spray (Nabiximols) in the Management of Chronic Pain. Journal of Pain Research.
