“Background: Fibromyalgia (FM) is a chronic pain condition characterized by widespread pain, fatigue, and functional impairment. Current pharmacological treatments show limited efficacy and poor tolerability. Cannabidiol (CBD) has demonstrated analgesic and anti-inflammatory properties, but evidence regarding CBD-containing topical formulations in FM remains scarce.
Objectives: To evaluate the feasibility, safety, and preliminary efficacy of a CBD-containing topical formulation for localized pain in patients with FM and to explore its potential impact on broader symptom domains.
Material and methods: This single-arm pilot study included 30 women with FM and clinically relevant localized pain due to musculoskeletal, neuropathic, or cutaneous comorbidities. Participants self-applied a commercially available CBD-containing topical formulation to a painful area every 8 h for 12 weeks. Outcomes were assessed at baseline, 4 weeks, and 12 weeks. Nonparametric repeated-measures analyses, Monte Carlo resampling, effect sizes, and minimal clinically important difference (MCID) thresholds were applied.
Results: At the 4- and 12-week follow-up visits, all participants reported full adherence to the prescribed application schedule. No adverse events or side effects were reported. Localized pain showed a significant and clinically meaningful reduction at 4 weeks, sustained at 12 weeks (60% achieving MCID). Functional capacity improved significantly, with 50% of participants exceeding the MCID at 4 weeks. Widespread Pain Index (WPI) and Symptom Severity Scale (SSS) scores decreased progressively, and a lower proportion of participants met the 2010 American College of Rheumatology (ACR) diagnostic criteria for FM at 12 weeks, while generalized pain, fatigue, anxiety, and depression did not show significant changes.
Conclusions: Topical application of a CBD-containing formulation was feasible and was associated with improvements in localized pain and functionality in this exploratory single-arm study. Changes observed in WPI and SSS, and in the proportion of participants meeting the 2010 ACR criteria at follow-up, should be interpreted cautiously and considered exploratory and hypothesis-generating, given the uncontrolled design (precluding causal inference), the symptom-based and fluctuating nature of FM, and the multicomponent composition of the product. Although limited by its uncontrolled design, this pilot study provides effect size estimates and methodological guidance to support future randomized controlled trials of topical cannabinoids in FM.”