How does not eating/fasting effect you when taking coumadin/warfarin? should i take lower dose if planning to fast? i plan on fasting for 72 hours.

Impossible to say: It would be impossible to say because of the many intricate effects of foods and beverages on coumadin (warfarin). I recommend you let your prescribing doctor know that you are fasting. I am sure your doctor will want you to get your inr checked right after the fast (and maybe before.).

Probably no effect: I am unaware of any alteration of Coumadin (warfarin) dosage when fasting. You might check with the doctor who is following your coumadin (warfarin).