Effects of N-acetylcysteine on systemic lupus erythematosus disease activity and its associated complications: a randomized double-blind clinical trial study

Backgrounds N-acetylcysteine (NAC) has broadly been used as an anti-oxidant agent in various types of diseases. This study aimed to assess the effect of NAC on the systemic lupus erythematosus (SLE) disease activity and outcome. Methods In this randomized, double-blind clinical trial study, 80 SLE patients were recruited that were classified into two groups: 40 patients received NAC (1800 mg/day; 3 times per day with 8-h intervals) for 3 months and 40 patients as the control group received normal therapies. Laboratory measurements and disease activity based on the British Isles Lupus Assessment Group (BILAG) and SLE Disease Activity Index (SLEDAI) were determined before the initiation of treatment and after the study time period. Results A statistically significant decrease in BILAG (P= 0.023) and SLEDAI (P= 0.034) scores after receiving NAC for a 3-month period was observed. BILAG (P= 0.021) and SLEDAI (P= 0.030) scores were significantly lower in NAC-receiving patients compared to the control group after 3 months. The disease activity in each organ based on BILAG score after treatment indicated a significant decrease in the NAC group compared to the baseline level in general (P=0.018), mucocutaneous (P=0.003), neurological (P=0.015), musculoskeletal (P=0.048), cardiorespiratory (P=0.047), renal (P=0.025), and vascular (P=0.048) complications. Analysis indicated a significant increase in CH50 level in the NAC group after treatment compared to the baseline level (P=0.049). No adverse event was reported by the study subjects. Conclusions It appears that the administration of 1800 mg/day NAC to SLE patients can decrease the SLE disease activity and its complications.