Background: Rheumatoid Arthritis (RA) is a common inflammatory disease of the
joints. Due to the importance of inflammation and oxidative stress in the pathogenesis of RA, drugs
that have anti-oxidant and anti-inflammatory properties, such as N-acetyl Cysteine (NAC), can be
used as adjunctive therapy in patients with RA.
Aims: The aim of this study was to evaluate the effects of oral NAC on inflammatory cytokines and
oxidative stress in patients with RA.
Methods: Adjunct to standard treatment, the NAC group (23 patients) received 600 mg of NAC
twice daily and the placebo group (19 patients) received identical placebo twice daily for 12 weeks.
Serum levels of Total Oxidant Status (TOS), Total Antioxidant Capacity (TAC), nitric oxide (NO),
Total Thiol Groups (TTG), Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-
6 (IL-6), C-reactive Protein (CRP), and Erythrocyte Sedimentation Rate (ESR) were
measured at baseline and at the end of the study.
Results: Results showed that in the NAC group, the serum levels of MDA, NO, IL-6, TNF-α, ESR
and CRP were significantly lower than the baseline. Also, the serum level of TAC and TTG, as
antioxidant parameters, increased significantly. However, only NO, MDA and TTG showed a significant
difference in the NAC group as compared to the placebo group at the end of study.
Conclusion: According to the results of this study, oral NAC can significantly reduce the several
oxidative stress factors and inflammatory cytokines. These results need to be confirmed in larger
studies while considering clinical outcomes of RA patients.