Methotrexate in the treatment of juvenile idiopathic arthritis

Low-dose methotrexate (MTX) is an established disease-modifying antirheumatic drug (DMARD) for the treatment of both juvenile idiopathic arthritis (JIA) and rheumatoid arthritis of adults (RA). However, in common clinical praxis, indication and application of MTX-treatment as well as monitoring of the respective side effects are differently managed. At the end of the eighties MTX was prescribed only to children,who were refractory to traditional slow-acting agents. In different clinical studies it has been found that MTX is a very safe and effective drug for treatment of JIA and that it is well tolerated in children. The common dosages of MTX in pediatric rheumatology ranges from 5-15 once a week, max. 250 mg/m(2)/week (0,2-0,8 mg/kg/week). The dosages given to children can be much higher than this given to RA patients (7.5-15 mg/week). This difference in dosage may be due to a different pharmakokinetic in children. Frequent side effects of MTX-treatment in children are gastrointestinal symptoms, like nausea and vomiting besides elevated liver enzymes and stomatitis. Thus, the weekly low dose MTX presents compared to other diseases-modifying antirheumatic drugs a beneficial efficiency-toxicity ratio in the treatment of juvenile idiopathic arthritis.