Tamoxifen Acenocoumarol

Gustovic P, Baldin B, Tricoire MJ, Chichmanian RM. Interaction tamoxifene-acenocoumarol. Une interaction potentiellement dangereuse. [Tamoxifen-acenocoumarol... 

In one retrospective analysis, 5 patients taking tamoxifen were very sensitive to warfarin, and, in a second, 5 of 22 patients had problems with over-anticoagulation. Case reports also describe over-anticoagulation in three women taking warfarin and one woman taking acenocoumarol when they also took tamoxifen. It has been suggested that a similar interaction may occur with toremifene. 

A 53-year-old woman who had been taking acenocoumarol for 2 years after a heart valve replacement died after a massive brain haemorrhage about 3 weeks after starting to take tamoxifen 20 mg daily for a benign breast condition. ... 

Evidence is limited to the above reports, but it appears that a clinically important interaction between tamoxifen and warfarin can occur, which apparently affects some but not all patients. Monitor the effects closely if tamoxifen is added to treatment with warfarin or acenocoumarol and reduce the dosage as necessary. The reports cited here indicate a reduction of between one-half to two-thirds for warfarin. In the US, when tamoxifen is being used for the primary prevention of breast cancer, the manufacturer specifically contraindicates concurrent use with warfarin or other coumarins. ... 

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See also in sourсe #XX -- [ ]

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