Yes, I was on warfarin (generic version of Coumadin) for awhile when I first started learning to skate. It was a very low dose for a chemo port. I never really asked my doctors or nurses about it, and they never expressed any concern either. I'm no longer taking the med. I was working on loop, flip and lutz, camel and sit spins (hmm, still working on same things!)
I didn't notice any difference in bruising from falls while I was on warfarin or after. The bruises from my more spectacular falls would be so deep that I wouldn't have much discoloration on the skin. I am pretty cautious and don't fall very often. When I do fall, they're usually fairly dramatic.