Pharmacokinetics of pirprofen in children with juvenile chronic arthritis.

Pirprofen (100 or 200 mg; Rengasil) was administered to experimental groups of children (children with juvenile chronic arthritis, JCA) and to a control group of children (children without JCA) as a single dose or as repeated doses. The pharmacokinetics of pirprofen in these children were compared to the pharmacokinetic parameter values obtained in healthy volunteers and in elderly arthritic adults receiving 400 mg of pirprofen. The children were examined regularly and laboratory values were determined in order to detect possible side effects. The results demonstrated that the pharmacokinetics of pirprofen were similar for children and adults when taking into account the dose and the body weight. There was no drug accumulation after repeated administration of pirprofen. As already observed in rheumatic adults, pirprofen remains in synovial fluid longer than in plasma.