Hemostasis (arrest of blood loss) and blood coagulation involve complex interactions between the injured vessel wall, platelets, and coagulation factors.
Vitamin K: K1 (from fat-soluble): phytonadione (phylloquinone)
: K3 (synthetic)
- Fat-soluble (Menadione, Acetomenaphthone)
- Water-soluble (Menadione sod. Bisulfite, Menadione sod. Diphosphate.
- Miscellaneous: Fibrinogen (human), Antihaemophilic factors, Desmopressin, Adrenochrome mono-semicarbazone, Rutin, Ethamsylate.
- Vit. K is a fat-soluble dietary principle required for the synthesis of clotting factors.
- Daily requirements: Vit. K2 produced by colonic bacteria and 3-10 µg/day external source may be sufficient. The total requirement of Vit. K for an adult has been estimated to be 50-100 µg/day.
Mechanism of Action:
- Vit. K acts as a cofactor at a late stage in the synthesis by the liver of coagulation proteins – prothrombin, factors VII, IX, and X.
- The only use of Vitamin K is in prophylaxis and treatment of bleeding due to deficiency of clotting factors.
- Deficiencies in plasma coagulation factors can cause bleeding.
- Factor VIII deficiency (classic hemophilia or hemophilia A) and factor IX deficiency (Christmas disease, or hemophilia B) account for most of the heritable coagulation defects. Concentrated plasma fractions and recombinant protein preparations are available for the treatment of these deficiencies.
- Desmopressin (DDAVP) stimulates the release of von Willebrand factor (Vwf) from the Weibel-palate bodies of endothelial cells, thereby increasing the levels of Vwf (as well as coagulant factor VIII) 3 to 5 fold.
- It is also used to promote the release of Vwf in patients with coagulation disorders such as von Willebrand disease, mild hemophilia A and thrombocytopenia.
- It is a plasma protein fraction obtainable from whole blood. It is used to treat deficiencies or qualitative abnormalities of fibrinogen.
- It may also be used for patients with factor VIII deficiency and Willebrand disease.
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