Hi, I'm concerned about my dad. He began taking coumadin a couple of weeks ago and when he had his blood checked this past week his vitamin k was too low I think, and he was severely anemic. He had been having bloody stools for a few days. Now he's in the hospital getting blood transfusions. Has anyone else experienced this... is this just a simple matter of having his dose changed or maybe he simply cannot take this medicine? This is the first time he's ever been on a blood thinner, even though he's had an ICD for over 3 years now. (He was diagnosed with cardiomyopathy, atrial fib, pulmonary edema, congestive heart failure... but he's been living for years with these conditions only taking blood pressure medicine until just recently. Now he's taking coumadin, digoxin, and lasix occasionaly... started taking all 3 of these just recently)