Comparative study of the pharmacokinetics of MTX in juvenile idiopathic arthritis patients receiving long-term MTX monotherapy or MTX plus chloroquine.
OBJECTIVE
To compare the pharmacokinetics and report on the clinical effects of methotrexate (MTX) in patients with juvenile idiopathic arthritis (JIA), receiving long-term MTX or MTX plus chloroquine (CQ).


METHODS
The pharmacokinetics of MTX, clinical characteristics (morning stiffness, joint tenderness and number of swollen joints) and biochemical markers (A-amyloid substance, C-reactive protein, erythrocyte sedimentation rate, fibrinogen and alpha-glycoprotein acid, alanine transaminase and aspartate transaminase) of the JIA patients were determined. Eight patients were treated with MTX (0.15 mg/kg) and another eight with MTX (0.15 mg/kg) plus CQ (4 mg/kg) for at least 6 months.


RESULTS
All patients had polyarticular involvement and the clinical characteristics and biochemical markers were similar for the two groups. The pharmacokinetics of MTX were also similar with the Cmax and AUC values being 455.00 +/- 101.00 nm and 1469.92 +/- 299.77 nm/h for MTX group and 425.00 +/- 169.60 nm and 1560.73 +/- 615.49 nm/h for MTX plus CQ group, respectively. The respective creatinine clearance was 117.95 +/- 12.58 for MTX group and 99.17 +/- 22.65 mL/min for MTX plus CQ.


CONCLUSIONS
The pharmacokinetics of MTX in JIA patients treated chronically with MTX are similar, with or without CQ co-treatment.
Kimura
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Department of Pharmacy and Pharmacology, State University of Maringá, Paraná, Brazil. ekimura@uem.br
Oga
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Pereira
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RM
D000293:Adolescent; D000328:Adult; D018501:Antirheumatic Agents / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001171:Arthritis, Juvenile; D002648:Child; D002738:Chloroquine / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage / Q000493:pharmacokinetics*
D018501:Antirheumatic Agents; D002738:Chloroquine; D008727:Methotrexate