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    Phenytoin Sodium Extended


    Hydantoins/Fluorouracil & Fluorouracil Prodrugs

    This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

    Medical warning:

    Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

    How the interaction occurs:

    When these two medicines are taken together, fluorouracil and medicines that become fluorouracil in the body may cause your liver to process your seizure medicine more slowly.

    What might happen:

    The blood levels of your seizure medicine may increase and cause toxic effects.

    What you should do about this interaction:

    Let your healthcare professionals ((e.g. doctor or pharmacist.) know that your are taking these medicines together. If you experience nausea, vomiting, confusion, dizziness, or other symptoms, contact your healthcare professional. It may be necessary to measure the blood levels of your seizure medicine. Your doctor may want to adjust the dose.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.


    1.Brickell K, Porter D, Thompson P. Phenytoin toxicity due to fluoropyrimidines (5FU/capecitabine): three case reports. Br J Cancer 2003 Aug 18;89(4):615-6.

    2.Rosemergy I, Findlay M. Phenytoin toxicity as a result of 5-fluorouracil administration. N Z Med J 2002 Aug 9;115(1159):U124.

    3.Gilbar PJ, Brodribb TR. Phenytoin and fluorouracil interaction. Ann Pharmacother 2001 Nov;35(11):1367-70.

    4.Uftoral (tegafur/uracil) UK summary of product characteristics. Merck Pharmaceuticals March 9, 2006.

    5.Wakisaka S, Shimauchi M, Kaji Y, Nonaka A, Kinoshita K. Acute phenytoin intoxication associated with the antineoplastic agent UFT. Fukuoka Igaku Zasshi 1990 Apr;81(4):192-6.

    Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

    CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

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