Deflazacort (DFZ) pharmacokinetics was evaluated in fifteen pediatric patients on chronic hemodialysis or after renal transplantation, and in three normal children. After overnight fasting, oral DFZ 0.26+/-0.01 mg/kg (mean +/- SEM) was given. Serial blood samples were collected for 360 min and analyzed by HPLC for 21-hydroxy-DFZ (21-HO-DFZ). Serum concentration profiles and pharmacokinetic parameters were similar in patients on hemodialysis, renal transplant recipients and normal children. Elimination half-life was longer in the 9 cyclosporine-treated subjects (108.0+/-13.6 min) than in the other nine (71.2+/-8.3 min; p <0.02). Our finding suggests that, from a pharmacokinetic point of view, DFZ dose adjustment for renal function is not necessary in children with chronic renal failure or after renal transplantation.