Cannabinoids for pain management in rheumatoid arthritis: a scoping review of clinical evidence and mechanisms.

Zintziovas N.; Karakosta A.; Voulgari P.; Stefanakis G.; Arnaoutoglou E.; Tzimas P.; Micha G. · Rheumatology international · 2026

**Background & Methods** This scoping review systematically searched four major databases (PubMed/MEDLINE, Scopus, DOAJ, and Cochrane Central Register) from January 1990 to September 2026 to identify clinical evidence on cannabinoid interventions for pain management in adults with rheumatoid arthritis (RA). The review included randomized controlled trials and observational studies reporting pain-related outcomes, with risk of bias assessed using Cochrane RoB 2 and ROBINS-I tools. **Key Findings** - The single randomized placebo-controlled trial (n=58) demonstrated that nabiximols significantly reduced pain on movement (0.95-point reduction, p=0.044) and pain at rest (1.04-point reduction, p=0.018), with improvement in sleep quality (1.17-point increase, p=0.027) and reduced disease activity as measured by DAS28 score (0.76-point decrease, p=0.002). - Two observational studies suggested possible symptomatic benefit from cannabinoid exposure but were substantially limited by heterogeneous cannabinoid formulations and serious to critical risk of bias. - Of 593 initial records identified, only three studies met eligibility criteria, indicating a substantial evidence gap in this research area. **Dosage & Administration** Not reported. The review identified nabiximols as the evaluated intervention in the RCT but did not specify dosing regimens or administration routes. **Safety & Adverse Effects** In the randomized trial, no serious adverse events were reported during the study period. However, the limited number of studies and their brief duration preclude comprehensive safety assessment. **Evidence Quality** Current evidence remains insufficient to establish cannabinoid efficacy or long-term safety for RA-related pain management. Major limitations include: (1) extremely limited RCT data (single trial with only 58 participants); (2) heterogeneous cannabinoid exposures and formulations across studies; (3) serious to critical risk of bias in observational studies; (4) lack of standardized pain outcome measures; and (5) absence of long-term safety data. The authors conclude that larger, rigorously designed trials using standardized cannabinoid formulations and validated pain-specific outcome measures are essential before clinical recommendations can be established.

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