title: Comparative pharmacokinetics of acetyl salicylic acid and its metabolites in children suffering from autoimmune diseases.
abstract: The aim of the present study was to compare the effect produced by juvenile rheumatoid arthritis (JRA) or rheumatic fever (RF) on the pharmacokinetics of acetyl salicylic acid (ASA) and its metabolites in children with autoimmune diseases (AD).
  
  
  METHODS
  A prospective, open labelled study was performed in 17 children with JRA and 17 with RF who received a single dose of 25 mg ASA/kg orally. The pharmacokinetics of ASA and its metabolites were determined. The blood and urine levels of each salicylate collected during 24 h were measured by HPLC. A group of 15 healthy teenage volunteers was included as a control group.
  
  
  RESULTS
  The maximum plasma concentration, half-life time, area under the curve and the amount of salicylates excreted were statistically different between the JRA and the RF groups, as well as between the RF group and the controls, however, there were no significant differences between the JRA group and the controls.
  
  
  CONCLUSIONS
  Dosage schemes must be adjusted for JRA patients, since the half life in these patients is longer than in RF patients. However, due to ample variability of pharmacokinetic parameters it is recommended that dose schemes are individualized on the type of autoimmune disease considered.
authors.affiliation: Laboratorio de Farmacología, Instituto Nacional de Pediatría (INP), México. juarezol@yahoo.com
authors.forename: Hugo
authors.initials: H
authors.lastname: Juárez Olguín
authors.forename: Janett
authors.initials: J
authors.lastname: Flores Pérez
authors.forename: Ismael
authors.initials: I
authors.lastname: Lares Asseff
authors.forename: Arturo
authors.initials: A
authors.lastname: Loredo Abdalá
authors.forename: Luis
authors.initials: L
authors.lastname: Carbajal Rodríguez
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D019540:Area Under Curve; D001171:Arthritis, Juvenile / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D001241:Aspirin / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics*; D001327:Autoimmune Diseases / Q000188:drug therapy* / Q000378:metabolism; D001682:Biological Availability; D002648:Child; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005841:Gentisates / Q000097:blood / Q000378:metabolism / Q000652:urine; D006207:Half-Life; D006626:Hippurates / Q000097:blood / Q000378:metabolism / Q000652:urine; D006801:Humans; D008297:Male; D008800:Mexico; D011446:Prospective Studies; D012213:Rheumatic Fever / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D020156:Salicylic Acid / Q000097:blood / Q000378:metabolism / Q000652:urine; D013607:Tablets
chemical_list: D005841:Gentisates; D006626:Hippurates; D013607:Tablets; C000693:salicylurate; D020156:Salicylic Acid; D001241:Aspirin; C010925:2,5-dihydroxybenzoic acid