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Menadione
- indication:The primary known function of vitamin K is to assist in the normal clotting of blood, but it may also play a role in normal bone calcification.
- pharmacologypharmacology:
- mechanism: Menadione (vitamin K3) is involved as a cofactor in the posttranslational gamma-carboxylation of glutamic acid residues of certain proteins in the body. These proteins include the vitamin K-dependent coagulation factors II (prothrombin), VII (proconvertin), IX (Christmas factor), X (Stuart factor), protein C, protein S, protein Zv and a growth-arrest-specific factor (Gas6). In contrast to the other vitamin K-dependent proteins in the blood coagulation cascade, protein C and protein X serve anticoagulant roles. The two vitamin K-dependent proteins found in bone are osteocalcin, also known as bone G1a (gamma-carboxyglutamate) protein or BGP, and the matrix G1a protein or MGP. Gamma-carboxylation is catalyzed by the vitamin K-dependent gamma-carboxylases. The reduced form of vitamin K, vitamin K hydroquinone, is the actual cofactor for the gamma-carboxylases. Proteins containing gamma-carboxyglutamate are called G1a proteins.
- toxicity: Menadione (vitamin K3), which is not used as a nutritional supplemental form of vitamin K for humans, has been reported to cause adverse reactions, including hemolytic anemia. Large doses have also been reported to cause brain damage.
- absorprion: Variable and ranges from 10% to 80%
- halflife:
- roouteelimination:
- volumedistribution:
- clearance: