l know a new anticoagulant called xarelto is being developed, but would this be a replacement for warfarin? Anyone know when this will be marketed and sold in the US?

Interesting question.

Xarelto (rivaroxaban) has been approved for use in Europe but is in Phase 3 trials in the US. If the drug proves to be effective & without serious side effects, it may be approved for use in the US, unless the FDA requires additional safety studies.

Rivaroxaban works in a different way than warfarin but will also prevent blood clotting. Similar intravenous (IV) drugs r currently approved for use in the US but require regular blood monitoring to avoid excessive bleeding. Since the trials have not been published, it is too early to tell if this drug will be better or worse than warfarin.