Drug General Information (ID: DDI9TP4FMY)
Drug Name			Tamoxifen		Drug Info		Anisindione		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antineoplastics				Anticoagulants
Structure

Mechanism of Tamoxifen-Anisindione Interaction (Severity Level: Major)
Increased risk of bleeding Click to Show/Hide Mechanism Graph
Drug Name		Tamoxifen				Anisindione
Mechanism		Potentiate the hypoprothrombinemic effect of vitamin K antagonist				Vitamin K antagonist
Key Mechanism Factor 1
		Factor Name		Bleeding
		Factor Description		Patients may be at risk for bleeding when the outcome of a disease or disease treatment confounds the standard mechanisms for maintaining hemostasis. Signs or symptoms of abnormal bleeding include: bleeding that takes a long time to stop (including nosebleeds, bleeding gums, bleeding from cuts and abrasions, and menstrual bleeding); severe unexplained bruising, or bruising that becomes larger; blood in the urine or stool, etc.
Mechanism Description		Increased risk of bleeding by the combination of Tamoxifen and Anisindione

Recommended Action
Management		The use of tamoxifen is considered contraindicated in women who require concomitant coumarin-type anticoagulants or in women with a history of deep vein thrombosis or pulmonary embolus. Where such coadministration exists, careful monitoring of the INR is recommended.

References
1	Product Information. Fareston (toremifene). Schering Laboratories, Kenilworth, NJ.
2	Product Information. Nolvadex (tamoxifen). Zeneca Pharmaceuticals, Wilmington, DE.
3	Ritchie LD, Grant SM "Tamoxifen-warfarin interaction: the Aberdeen hospitals drug file." BMJ 298 (1989): 1253. [PMID: 2502242]