Q. I have been drinking a lot of cranberry juice to ward off a urinary tract infection. I have also been eating dried cranberries as a snack. Is it possible this could affect Coumadin? My blood work (INR) is now out of bounds. I haven’t changed anything else in my diet.
A. There have been several cases of cranberries increasing the blood thinning potential of Coumadin (warfarin). A fatal hemorrhage attributed to the combination of cranberry juice and warfarin was reported last year.
Scientists have investigated this possible interaction and found that susceptible people may experience a 30 percent increase in anticoagulant activity when cranberry is consumed with Coumadin (British Journal of Pharmacology, Aug. 2008). This suggests that cranberries could pose problems in combination with warfarin.
