title: Plasma and cerebrospinal fluid pharmacokinetics of naproxen in children.
abstract: The aim of this study was to characterize pediatric pharmacokinetics and central nervous system exposure of naproxen after oral administration. The pharmacokinetics of naproxen was studied in 53 healthy children aged 3 months to 12 years undergoing surgery with spinal anesthesia. Children received preoperatively a single dose of 10 mg/kg oral naproxen suspension. A single cerebrospinal fluid (CSF) sample (n = 52) was collected at the induction of anesthesia, and plasma samples (n = 270) were collected before, during, and after the operation (up to 51 hours after administration). A population pharmacokinetic model was built using the NONMEM software. Naproxen concentrations in plasma were well described by a 2-compartment model. The estimated oral clearance (CL/F) was 0.62 L/h when linearly scaled by weight to 70 kg. The apparent volume of distribution at steady state (Vss/F) was 12.5 L /70 kg. The findings are consistent with previously reported pharmacokinetic parameters for children older than 5 years. Naproxen permeated into the CSF and reached CSF concentrations that were 4 times higher than unbound plasma concentrations. Based on these data, weight can be used as a basis for naproxen dosing in children older than 3 months of age.
authors: Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland. pyry.valitalo@uef.fi
authors: Pyry
authors: P
authors: Välitalo
authors: Elina
authors: E
authors: Kumpulainen
authors: Minna
authors: M
authors: Manner
authors: Merja
authors: M
authors: Kokki
authors: Marko
authors: M
authors: Lehtonen
authors: Andrew C
authors: AC
authors: Hooker
authors: Veli-Pekka
authors: VP
authors: Ranta
authors: Hannu
authors: H
authors: Kokki
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008954:Models, Biological; D009288:Naproxen / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D009288:Naproxen