Pharmacokinetics of etodolac in patients with stable juvenile rheumatoid arthritis.

This was a single-center, open-label, single-dose pharmacokinetic study of etodolac in pediatric and adolescent patients with stable juvenile rheumatoid arthritis (JRA). Eleven male and female patients with JRA (8.1 to 14.8 years of age, weighing 26.4 to 59.5 kg) received a single oral dose of etodolac (200, 300, or 400 mg based on body weight). Clinical laboratory measurements, measurement of vital signs, and physical examinations were performed to monitor safety. Concentrations of etodolac were determined in plasma using high-performance liquid chromatography with ultraviolet detection with a limit of quantitation of 0.2 mg/L and were analyzed using a noncompartmental pharmacokinetic method. Pharmacokinetic parameters observed were consistent in magnitude and degree of variability with data from healthy adult subjects receiving a single 400- or 600-mg dose of etodolac. Although the mean fraction of unbound drug in patients with JRA was higher than in healthy adults, the oral clearance was independent of age. No serious adverse events occurred during this study. Etodolac yielded consistent pharmacokinetic values among stratified dose subgroups. Single doses of all etodolac treatments were well tolerated in both pediatric and adolescent patients.