Long-term effects of azathioprine therapy for juvenile rheumatoid arthritis

Background and purpose:Juvenile rheumatoid arthritis (JRA) can result in di sability, growth disturbance, and systemic complications. This study invest igated the efficacy and adverse effects of azathioprine (AZA) therapy in ch ildren with JRA. Methods: Data from the medical records of 24 children with JRA treated with oral AZA during the period from 1988 to 1998 were retrospectively anal)zed . All 24 patients had received two or more nonsteroidal anti-inflammatory d rugs (NSAIDs) and 12 had received disease-modifying antirheumatic drugs (DM ARDs) prior to the start of AZA Of the 24 patients, 21 were corticosteroid- dependent prior to the onset of AZA therapy. The indication for AZA therapy was lack of efficacy of the current treatment regimen. The initial and max imal doses of AZA averaged 1.7 mg.kg(-1).d(-1) (range, 1-3 mg kg(-1). d(-1) ) and 1.9 mg.kg(-1)d(-1) (range, 1-6 mg.kg(-1).d(-1)), respectively. The me an duration of treatment was 13 months (range, 4-37 mo). The mean duration of follow-up was 45 months (range, 7-137 mo) from the start of AZA therapy. Results: Fifteen children (62.5%) showed clinical improvement, while die ot her nine (37.5%) achieved clinical remission. AZA treatment resulted in a m ore than 50% reduction in the required corticosteroid dose in seven childre n and complete discontinuation of corticosteroid administration in eight ch ildren. None of die patients treated with AZA doses of 1 to 3 mg.kg(-1).d(- 1) developed AZA-related side effects. Two patients suffered from AZA-relat ed adverse effects due to AZA overdose (6 mg.kg(-1).d(-1)). Both experience d pancytopenia and disseminated infection, which resolved following reducti on of the AZA dose to 3 mg.kg(-1).d(-1). Conclusions: AZA is an effective and well-tolerated steroid-sparing agent f or JRA refractory to NSAIDs or DMARDs.