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:
Certain medications may decrease the effect of tamoxifen by interfering with how the body activates tamoxifen. Amiodarone, thioridazine, and tamoxifen can all affect your heart's rhythm.
What might happen:
Your tamoxifen may not work as well at preventing your breast cancer from returning. Taking amiodarone or thioridazine with tamoxifen may increase your risk of an irregular heartbeat, which may be life-threatening.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are using these products together. Your doctor may want to change your medicine. Let your doctor know right away if you notice an irregular heartbeat or have any dizziness or fainting episodes.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.
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