Methotrexate in juvenile rheumatoid arthritis. Do the benefits outweigh the risks?

Juvenile rheumatoid arthritis (JRA) is a heterogeneous group of autoimmune diseases resulting in chronic idiopathic peripheral arthritis. The aetiology of JRA is unclear, and current pharmacotherapy is ameliorative rather than curative. Nonsteroidal anti-inflammatory drugs are given initially, but only one-third to one-fourth of patients are managed adequately with these agents. Advanced therapeutic drugs, frequently referred to as disease-modifying antirheumatic drugs or second-line agents, are given to the child with aggressive or resistant disease. Among these, the antimetabolite methotrexate has proven to be the most effective in alleviating articular disease manifestations and reducing laboratory parameters of inflammation. When given orally in low dosages (10 to 15 mg/m2/week), methotrexate is well tolerated, without evidence of substantial bone marrow suppression or severe hepatotoxicity. Extensive long term tolerability data are not yet available for children, but longitudinal studies in adult patients with rheumatoid arthritis suggest that the drug may be given safely for extended periods in many patients. Paediatric rheumatologists are beginning to give higher dosages of methotrexate (up to 1 mg/kg/week) parenterally with some success. The long term consequences of higher dose methotrexate in children are unknown. Methotrexate has now become, and will probably remain for some time, the drug of first choice for children with recalcitrant JRA.