I have heard that glucosamine can have an interaction with warfarin. Is that true?
It is possible, yes. A recent study reported that glucosamine can possibly interfere with the international normalized ratio or (INR). The INR is a standardized blood test used to monitor the effects of anticoagulant medications such as warfarin. It appears that for some individuals using warfarin or similar anticoagulants, simultaneously taking supplements containing glucosamine will cause an inaccurate reading on the INR. The United States Food & Drug Administration (FDA) has thus far reported 20 such cases on its MedWatch database, and the World Health Organization (WHO) has 21 cases of glucosamine interference with INR readings, 17 of which were resolved when glucosamine supplementation ceased. These figures are indeed miniscule considering the number of people using glucosamine, which has now entered the nutritional supplement mainstream along with such mainstays as multivitamins/minerals and vitamin C. In fact, in Canada, the Natural Health Products Directorate (the branch of Hea
