Comparative pharmacokinetics of acetyl salicylic acid and its metabolites in children suffering from autoimmune diseases.
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.
Juárez Olguín
Hugo
H
Laboratorio de Farmacología, Instituto Nacional de Pediatría (INP), México. juarezol@yahoo.com
Flores Pérez
Janett
J
Lares Asseff
Ismael
I
Loredo Abdalá
Arturo
A
Carbajal Rodríguez
Luis
L
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
D005841:Gentisates; D006626:Hippurates; D013607:Tablets; C000693:salicylurate; D020156:Salicylic Acid; D001241:Aspirin; C010925:2,5-dihydroxybenzoic acid