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MR Vol.14 No.2 indexに戻る
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MODERN RHEUMATOLOGY
Vol.14 No.2 |
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Pharmacokinetics and efficacy of low-dose methotrexate
in patients with rheumatoid arthritis |
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| Yoshiko Hiraga1, Yoshimitsu Yuhki1, Katsumi Itoh1,
Kohji Tadano1, Yasushi Takahashi1 and Masaya Mukai2 |
(1) Department of Pharmacy, Sapporo City General
Hospital, Sapporo, Japan
(2) Division of Clinical Immunology and Hematology, Department of Medicine, Sapporo
City General
Hospital, Kita 11-jo, Nishi 13-chome, Chuo-ku, Sapporo, 060-8604, Japan |
Received: 25 June 2003 Accepted: 09 December
2003 |
| Abstract |
| This article evaluates the relationship between
the pharmacokinetics of methotrexate (MTX), its efficacy in the treatment
of rheumatoid arthritis (RA), and serum folic acid (FA) levels. The
pharmacokinetics of MTX was studied in 29 patients with RA treated
with low-dose MTX. The weekly dose of MTX was given orally at 2?4mg
every 12h over a period of 24?36h. Blood samples were taken 4h after
the first administration in any given week. A Bayesian method was
used to estimate individual MTX pharmacokinetic variables. We then
investigated the efficacy of MTX and the serum FA levels in these
patients. We examined C-reactive protein levels (CRP) and the erythrocyte
sedimentation rate (ESR), and analyzed the values obtained before
and after MTX treatment in order to evaluate the efficacy of the
MTX treatment. The degree of improvement in CRP and ESR was significantly
correlated with the length of time the MTX concentration?time curve
remained above 0.02μM in one week. Furthermore, the degree of improvement
in CRP was also significantly correlated with the area under the
concentration?time curve (AUC) for MTX. These results suggest that
serum MTX measurements could be useful in determining individual
patient regimens. |
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| Key words |
| Methotrexate (MTX) - Pharmacokinetics - Rheumatoid
arthritis (RA) |
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