The effect of folic acid supplementation on the toxicity of low-dose methotrexate in patients with rheumatoid arthritis

Authors

  • Sarah L. Morgan Md, Rd, Facp,

    Corresponding author
    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
    • The University of Alabama at Birmingham, Department of Nutrition Sciences, Webb Building—202, UAB Station, Birmingham, AL 35294
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  • Joseph E. Baggott PhD,

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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  • William H. Vaughn BS,

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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  • Peggy K. Young CMA,

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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  • Janet V. Austin BS,

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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  • Carlos L. Krumdieck Md, Phd,

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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  • Graciela S. Alarcon Md, Mph, Facp

    1. Department of Nutrition Sciences and the Division of Clinical Immunology and Rheumatology, Department of Medicine, The University of Alabama at Birmingham.
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Abstract

Thirty-two patients with rheumatoid arthritis completed a 24-week, placebo-controlled, double-blind trial of folic acid (FA) supplementation during low-dose methotrexate (MTX) therapy. Administration of the daily FA supplement significantly lowered toxicity scores without affecting efficacy, as measured by joint counts, joint indices, and patient and physician evaluation of disease activity. Fifteen patients experienced some sort of toxicity; 67% were in the placebo group, and 33% were in the FA supplement group. Four patients in the placebo group had toxicity levels serious enough to require discontinuation of the MTX, while no patients in the FA supplement group discontinued MTX because of toxicity. Low-normal initial plasma and red blood cell folate levels were predictive of future toxicity with MTX therapy. We conclude that a daily supplement of 1 mg of FA during low-dose MTX therapy (median dose 7.5 mg/week [16.4 μmoles]) is useful in lessening toxicity without altering efficacy during the first 6 months of treatment.

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