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:
The cause of the interaction is not known. When these two medicines are taken together, your body may not process one or both medicines properly.
What might happen:
You may experience an increased chance for bleeding including bleeding from your gums, nosebleeds, unusual bruising, or dark stools.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about taking these two medicines together. They may already be aware of this interaction and may be monitoring you for it. If your doctor prescribes these medicines together, it may be necessary to check your bleeding times more often. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Nolvadex (tamoxifen citrate) US prescribing information. AstraZeneca Pharmaceuticals LP March, 2006.
2.Fareston (toremifene citrate) US prescribing information. GTx, Inc. March, 2011.
3.Tenni P, Lalich DL, Byrne MJ. Life threatening interaction between tamoxifen and warfarin. BMJ 1989 Jan 14;298(6666):93.
4.Lodwick R, McConkey B, Brown AM. Life threatening interaction between tamoxifen and warfarin. Br Med J (Clin Res Ed) 1987 Oct 31;295(6606):1141.
5.Ritchie LD, Grant SM. Tamoxifen-warfarin interaction: the Aberdeen hospitals drug file. BMJ 1989 May 6;298(6682):1253.