Pharmacokinetics of ibuprofen in febrile children.

Ibuprofen may be an alternative to acetaminophen to control fever in children but little is known about its pharmacokinetics in pediatric patients. We studied 17 patients (age 3-10 yr) with fever; the most prevalent diagnoses were streptococcal pharyngitis and otitis media. Ibuprofen liquid was given as a single dose, 5 mg/kg (9 patients) or 10 mg/kg (8 patients). Multiple blood samples were collected over 8 hours and analyzed by HPLC. The maximum observed serum concentrations of ibuprofen ranged from 17-42 micrograms.ml-1 at 5 mg.kg-1 and 25-53 micrograms.ml-1 at 10 mg.kg-1 doses. Pharmacokinetics did not appear to be affected by ibuprofen dose. Mean tmax, oral clearance and elimination half life were 1.1 h, 1.2 ml.min-1.kg-1, and 1.6 h, respectively in patients at 5 mg.kg-1 doses; the corresponding values were 1.2 h, 1.4 ml.min-1.kg-1, and 1.6 h in those receiving 10 mg.kg-1 doses. There was no relationship between age and ibuprofen kinetics. No adverse effects occurred in any patients. These data suggest that ibuprofen pharmacokinetics may not be affected by dose between 5 and 10 mg/kg or age between 3 and 10 years.