Sinomenine versus NSAIDs for the treatment of rheumatoid arthritis: A systematic review and meta-analysis

Sinomenine (SIN), an alkaloid isolated from Caulis sinomenii, has been used in the treatment of rheumatoid arthritis (RA) clinically. This study aimed to systematically evaluate the efficacy and safety of SIN by a comparison between SIN and non-steroidal anti-inflammatory drugs (NSAIDs). Forty-three electronic databases were systematically searched. The quality of eligible trials was assessed by Jadad's scale. Revman 5.0 software was used for data syntheses and meta-analyses. The results showed that (i) of the 121 potential studies identified, 10 clinical trials involving 1185 patients met the inclusion criteria; (ii) improved patients and rheumatoid factor disappearance patients after SIN treatments were significantly more than those treated by NSAIDs (P < 0.00001 and P = 0.008); (iii) compared with NSAIDs, SIN was more effective in amelioration of morning stiffness (P < 0.00001), painful joints (P = 0.03), and erythrocyte sedimentation rate (P < 0.00001), but there was no significant difference between the two remedies in the treatment of swollen joints, grip strength, and C-reactive protein (P > 0.05); and (iv) adverse events occurred less frequently in the digestive system during SIN treatment than during NSAID treatment (P = 0.0003) but occurred more frequently in the dermatomucosal system with SIN treatment (P = 0.03), while adverse events of the nervous system were similar for both treatments (P = 0.31). In conclusion, SIN may be a valuable remedy to treat RA clinically, although current evidence needs to be further verified by more high-quality trials.