Bioavailability of MTX in Adult RA patients oral/parenteral

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Mike Bartolatz
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Bioavailability of MTX in Adult RA patients oral/parenteral

Post by Mike Bartolatz » Mon Apr 12, 2004 1:23 pm

> Bioavailability of Higher Dose Methotrexate Comparing Oral and
> Subcutaneous Administration in Patients with Rheumatoid Arthritis
> http://www.jrheum.com/abstracts/abstracts04/645.html
>
> MONIQUE HOEKSTRA, CEES HAAGSMA, CEES NEEF, JOHANNES PROOST, ANTONIUS
> KNUIF, and MART van de LAAR
>
> ABSTRACT.
>
> Objective. To determine the bioavailability of higher oral doses of
> methotrexate (MTX) in adult patients with rheumatoid arthritis (RA).
>
> Methods. A pharmacokinetic analysis was performed in 15 patients with RA
> taking a stable dose of MTX (³ 25 mg weekly). Separated by 2 weeks, a
> pharmacokinetic analysis was performed in each patient after oral and
> subcutaneous administration of the same dose of MTX. MTX serum
> concentrations were measured by a fluorescence polarization immunoassay.
> Pharmacokinetic analysis was performed with an iterative 2-stage
> Bayesian population procedure, obtaining population and individual
> pharmacokinetic parameters.
>
> Results. The median MTX dose was 30 mg weekly (range 25–40 mg). A
> 2-compartment model best described the serum MTX concentration versus
> time curves. The mean bioavailability after oral MTX was 0.64 (range
> 0.21–0.96) compared to subcutaneous administration. There was a
> statistically significant difference in the bioavailability of the 2
> administration regimens.
>
> Conclusion. Bioavailability of a higher oral dose of MTX in adult
> patients with RA is highly variable, and on average two-thirds that of
> the subcutaneous administration. To improve efficacy of MTX at dosages
> of 25 mg weekly or more, a change to parenteral administration should be
> considered. (J Rheumatol 2004;31:645-8)
>
> Key Indexing Terms:
> METHOTREXATE
> PHARMACOKINETICS
> RHEUMATOID ARTHRITIS
>
> From the Department of Rheumatology, and the Department of Clinical
> Pharmacology, Medisch Spectrum Twente, Enschede; and the Department of
> Pharmacokinetics and Drug Delivery, University Centre for Pharmacy,
> Groningen, The Netherlands.
>
> M. Hoekstra, MD, Rheumatologist; C.J. Haagsma, MD, Rheumatologist;
> M.A.F.J. van de Laar, MD, Rheumatologist, Department of Rheumatology,
> Medisch Spectrum Twente; C. Neef, PhD, Hospital Pharmacist; A.J.H.
> Knuif, Pharmaceutical Analyst, Department of Clinical Pharmacology,
> Medisch Spectrum Twente; J.H. Proost, PhD, Pharmacist, Department of
> Pharmacokinetics and Drug Delivery, University Centre for Pharmacy.
>
> Address reprint requests to Dr. M. Hoekstra, Department of Rheumatology,
> Medisch Spectrum Twente, PO Box 50000, 7500 KA Enschede, The
> Netherlands. E-mail: m.hoekstra@ziekenhuis-mst.nl
>
>
>
>
Last edited by Mike Bartolatz on Mon Feb 05, 2007 11:54 am, edited 1 time in total.
Mike Bartolatz
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Post by Guest » Sun Mar 19, 2006 4:43 am

Thanks, you help me.
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