Therapeutic efficacy of Urtica dioica and evening primrose in patients with rheumatoid arthritis: A randomized double-blind, placebo-controlled clinical trial

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease. The pharmacological therapy of RA is often symptomatic to mitigate pain and immobility with analgesics and drugs with defined side effects and risks. Complementary medicines might decrease the signs of RA and reduce the need for them. In the present study, the anti-rheumatic, anti-inflammatory, and anti-oxidant effects of Urtica dioica and Evening Primrose Oil (EPO), in patients with RA was investigated. This randomized, double‐blind, controlled trial involved 90 RA patients, and randomly assigned them into EPO, Urtica dioica, and placebo groups. The potential effect of these herbal medicines on Disease Activity Score (DAS) 28, Visual Analogue Scale (VAS), Total Anti-oxidant Capacity (TAC), IL-17, Rheumatoid Factor (RF), anti-cyclic citrullinated peptide antibodies (Anti-CCP), C Reactive Protein (CRP), and Erythrocyte Sedimentation Rate (ESR) before and after clinical trial were evaluated. After a three-month follow-up, the mean values of DAS28, IL-17, TAC, RF, and CRP in EPO and Urtica dioica groups were significantly different from the placebo group. However, the VAS, Anti-CCP, and ESR at baseline and at the end of the study were not significantly different between the three groups. After the intervention, the within-group DAS28 in the EPO and Urtica dioica groups, and placebo groups reduced significantly compared to the baseline. Medicinal plants EPO and Urtica dioica appeared to decrease inflammatory factors, and can improve the symptoms of RA. Thus, EPO and Urtica dioica have great potential as complementary therapy in RA patients.