Tamoxifen Oral Medication Interactions

  • Interactions

    Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

    This drug should not be used with the following medications because very serious interactions may occur:

    • anastrozole
    • letrozole

    If you are currently using any of these medications listed above, tell your doctor or pharmacist before starting tamoxifen.

    Tell your doctor or pharmacist of all prescription and nonprescription drugs you may use, especially of:

    • "blood thinners" (e.g., warfarin)
    • bupropion
    • estrogens
    • hormonal forms of birth control (e.g., birth control pills, patches, implants)
    • phenobarbital
    • rifamycins (e.g., rifampin)
    • St John's wort

    Other medications can affect the removal of tamoxifen from your body, which may affect how tamoxifen works. Examples include cimetidine, SSRI antidepressants such as fluoxetine/paroxetine, among others.

    This medication may interfere with certain laboratory tests (including thyroid tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

    This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.