The pharmacokinetics of ibuprofen suspension, chewable tablets, and tablets in children with cystic fibrosis

Objectives: The objectives of this study were to compare the pharmacokineti c parameters of ibuprofen administered as a suspension, chewable tablet, or tablet in children with cystic fibrosis and to determine the optimal blood sampling times for measuring ibuprofen peak concentrations. Study design: A single oral 20 mg/kg dose of ibuprofen was administered, an d blood samples were obtained at 15, 30, 45, 60, 120, 240, and 360 minutes after the dose was administered. Peak plasma concentration (C-max), time to peak concentration (T-max), and other pharmacokinetic parameters were dete rmined and compared (analysis of variance and analysis of covariance). Results: Thirty-eight children were included (22, 4, and 12 in the suspensi on, chewable tablet, and tablet groups, respectively). T-max was the only p arameter for which statistical differences were noted (suspension vs tablet , P less than or equal to.02). After age and sex were removed as potential confounding variables, T-max remained statistically different (P less than or equal to.001). Conclusions: A 20 mg/kg dose of ibuprofen suspension is recommended, with b lood samples for pharmacokinetic analysis obtained 30, 45, and 60 minutes a fter the dose is administered. Obtaining the first blood sample hour after dose administration will miss similar to 90% of peak concentrations, increa sing the likelihood of overdosing.