Summary: Coumadin is usually completely absorbed when taken by mouth. Differences in doses from one to another person occur because Coumadin in the liver is altered by at least two different proteins that determine how long the Coumadin will remain as an active drug. VKOR and CYP2C9 are these proteins and they are genetically determined for each of us. Research is ongoing right now, funded by Medicare, to see If we can determine early Coumadin doses by measuring these proteins, and if this information gives us a safer dose range that translates into less bleeding, and less rethrombosis.
