is given to prevent stroke
in a patient who has A.fib
more beneficial is to control his BP first ,
continue your present dose of coumadin , and dose of it should be modified in consultation with cardiologist with regular monitoring of INR level as if INR increase to certain level it will also increase chances of bleeding .
avoid green leafy vegetables in diet as it will also decrease coumadin effect ,
consult your cardiologist and try to adjust your BP medicine first