Objective: Oxidative stress and Overproduction of pro-inflammatory cytokines are contributed
in Rheumatoid Arthritis (RA) pathogenesis. N-acetylcysteine (NAC) is an antioxidant and antiinflammatory
agent which demonstrated analgesic effects in some studies. This study is designed to
assess the effects of oral NAC as an adjuvant therapy on the clinical outcomes of patients with active
Methods: In this randomized clinical trial, 51 RA patients with active RA were studied in 2 groups:
NAC group (27 patients) received standard treatment of RA and 600 mg NAC twice a day for 12
weeks, and placebo group (24 patients) received the standard treatment of RA and placebo. Disease
activity score (DAS28) was used to assess the activity of RA, Visual Analog Scale (VAS) for the
severity of pain, Health Assessment Questionnaire (HAQ) for the patients’ physical performance, and
Global Health (GH) parameter for the patients’ assessment of their disease activity. The number of
tender and swollen joints and Erythrocyte Sedimentation Rate (ESR) were also determined for each
patient. Data were analyzed using SPSS version 16.0 (Chicago, IL, USA).
Results: After 12 weeks of intervention, there were no significant differences between two groups in
DAS28 score and ESR (P values were 0.4 and 0.6, respectively). However, GH, VAS, and HAQ
scores were improved significantly in the NAC group compared to the placebo group.
Conclusion: Our findings indicate that oral administration of NAC may be associated with improving
health status in RA patients and considered as an adjuvant therapy in these patients. Further studies
with larger sample size, longer study duration and higher doses of NAC are needed to confirm the effects
of oral NAC in RA patients.