TOPLINE:

In patients with fibromyalgia, a 24-week treatment with a 50-mg/d dose of plant-derived cannabidiol did not outperform placebo in terms of pain relief or health-related quality of life. The only significant improvement achieved with cannabidiol was for observed nightly rest.

METHODOLOGY:

• Researchers conducted a randomized double-blind trial at a specialized fibromyalgia outpatient clinic in Denmark to determine whether cannabidiol was effective and safe for treating fibromyalgia.
• They included 200 adults with fibromyalgia (mean age, 49.9 years; 94.5% women) between April 2021 and April 2023. The participants had an average pain intensity score of ≥ 4 on a numeric rating scale (NRS) and had not used cannabis in the past 6 months.
• Overall, 100 patients each were randomly assigned to receive oral tablets of either 50 mg/d of cannabidiol or a placebo for 24 weeks.
• The primary outcome was a change in pain intensity at 24 weeks, assessed using an NRS subscale of the revised Fibromyalgia Impact Questionnaire, in which 0 indicated no pain and 10 indicated worst pain.
• Several secondary outcomes, including changes in sleep quality and duration, observed nightly rest, and health-related quality of life, were assessed; the safety monitoring included the reporting of adverse events.

TAKEAWAY:

• At week 24, pain intensity reduced by a mean of 0.4 points in patients who received cannabidiol and by 1.1 points in those who received the placebo; the 0.7-point difference between the groups that favored the placebo (P = .0028) was not clinically meaningful.
• Fewer patients on cannabidiol than on placebo achieved pain relief responses such as an improvement of more than 1 unit in NRS score and a 30% or 50% improvement in pain. Patients on placebo reported greater improvements in health-related quality of life than those on cannabidiol.
• The cannabidiol group reported 22 minutes longer observed nightly rest than the placebo group (between-group difference, 0.37 hours; 95% CI, 0.16-0.58).
• Both groups had similar rates of adverse events ; however, more participants in the placebo group experienced serious adverse events than those in the cannabidiol group. Headaches, fatigue, nausea or vomiting, and gastrointestinal symptoms were the most common adverse events.

IN PRACTICE:

“[This] study did not support analgesic efficacy of treatment with [cannabidiol] 50 mg daily compared to placebo in patients with fibromyalgia,” the authors of the study wrote.

SOURCE:

This study was led by Marianne Uggen Rasmussen, PhD, Parker Institute, Bispebjerg and Frederiksberg Hospital, Frederiksberg, Denmark. It was published online on August 21, 2025, in Annals of the Rheumatic Diseases.

LIMITATIONS:

This single-center study recruited patients from a specialized outpatient clinic, which may not reflect the broader patient population. Women comprised the majority of the study population. Data on the use of cannabis-related products before the 6-month period was not available.

DISCLOSURES:

This study received funding from multiple sources, including the Danish Rheumatism Association, Erna Hamilton Foundation, and Aase and Ejnar Danielsen Foundation. The investigational products were partly sponsored by Nordic Cannabis Research, Denmark, and Linnea Natural Pharma Solutions, Switzerland. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.