RESUMO
UNLABELLED: 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.
Assuntos
Artrite Juvenil/tratamento farmacológico , Aspirina/metabolismo , Aspirina/farmacocinética , Doenças Autoimunes/tratamento farmacológico , Febre Reumática/tratamento farmacológico , Administração Oral , Adolescente , Área Sob a Curva , Artrite Juvenil/sangue , Artrite Juvenil/urina , Aspirina/administração & dosagem , Doenças Autoimunes/metabolismo , Disponibilidade Biológica , Criança , Cromatografia Líquida de Alta Pressão , Feminino , Gentisatos/sangue , Gentisatos/metabolismo , Gentisatos/urina , Meia-Vida , Hipuratos/sangue , Hipuratos/metabolismo , Hipuratos/urina , Humanos , Masculino , México , Estudos Prospectivos , Febre Reumática/sangue , Febre Reumática/urina , Ácido Salicílico/sangue , Ácido Salicílico/metabolismo , Ácido Salicílico/urina , ComprimidosRESUMO
OBJECTIVE: To study the biochemical markers of bone turnover in children with juvenile chronic arthritis (JCA) and to compare these parameters with those in healthy children in order to evaluate the relationships between age, disease activity and biochemical variables. METHODS: Sixty-two children with JCA and 157 healthy children were studied. Serum samples were analyzed for their concentrations of minerals, osteocalcin (OC) and bone-specific alkaline phosphatase (BAP). Urine samples were examined to monitor the excretion of hydroxyproline (HYP) and deoxypyridinoline crosslinks (DPD). RESULTS: OC, BAP, HYP/Cr, DPD/Cr values were decreased in healthy girls more than 12 years of age and in healthy boys more than 14 years of age compared to younger children from the same population. Lower levels of OC and BAP were observed in younger children with JCA (girls < or = 12 yrs.; boys < or = 14 yrs.) compared to healthy children of the same age. Older girls with JCA (> or = 13 yrs.) were found to have increased HYP/Cr and DPD/Cr values compared to older healthy children. CONCLUSION: These results indicate that abnormalities of bone metabolism occur in an age-related fashion in JCA. This was demonstrated by a reduction in the markers of bone formation in younger JCA patients. Moreover, in older girls the markers of bone resorption were found to be elevated. Taken together, these findings suggest that bone formation is reduced from early childhood to mid-puberty, while resorption levels increase in children with JCA after this time.