Vitamin K antagonists (VKA) are a class of anticoagulants which , as their name indicates act by inhibiting the action of vitamin K, coumarins are the most commonly used VKA. In medicine the most commonly used VKA is warfarin.. Warfarin is an antagonist of Vitamin K, a necessary element in the synthesis of clotting factors II, VII, IX, and X as well as the naturally occuring endogenous anticoagulatant protein C and S which are biologically inactive without the carboxylation of certain glutamic acid residues. This carboxylation process requires reduced Vitamin K as a co-factor.
Coagulation is the process by which a liquid changes to a semi-solid mass or a gel. When a cut occur on our body with bleeding,with a little pressure and bandaging of the wound bleedings stops. Here clotting factors in the blood becomes active and change the liquid blood into a gel (clot). When the wound is healed and the clot is no longer needed, the body gradually reabsorbs the clot. This is blood clotting. It is an important process that prevents excessive bleeding from an injury, but if the body does not reabsorbs the clot it becomes life threatening.