METHOTREXATE PHARMACOKINETICS IN PATIENTS WITH RHEUMATOID-ARTHRITIS

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  • 1 June 1989
    • journal article
    • research article
    • Vol. 16  (6) , 745-748
Abstract
Few studies have evaluated the pharmacokinetics of low dose oral methotrexate (MTX) therapy. MTX pharmacokinetics were studied in 10 patients with classic rheumatoid arthritis (RA) after a single 7.5 mg oral dose. MTX was rapidly absorbed. Peak concentrations varied considerably, ranging from 0.31-0.72 .mu.M. Measurable drug concentration was found in all patients at 24 h after the dose. CL/F-MTX = 145 .+-. 52 ml/min1.73 m2 and elimination half-life was 4.5 .+-. 0.89 h. Oral MTx given as a single weekly dose has predictable pharmacokinetics. Further studies to examine what relationship exists, if any, with efficacy and toxicity of MTX in RA must be undertaken.