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vitamin K
Physiology:
1) cofactor in post-translational modifications by vitamin-K dependent carboxylase
a) coagulation factors II, VII, IX & X
b) protein C is a vitamin K dependent serine protease
c) protein S is a vitamin K-dependent binding protein
2) results in amino terminal gamma-carboxyglutamate residues
3) negatively charged gamma-carboxyglutamate bind Ca+2 & mediate adherence of coagulation factors to the surface of activated platelets
Pharmacology:
- warfarin inhibits synthesis of vitamin K-dependent coagulation factors (II, VII, IX & X)
Dosage:
1) Minimum daily requirements:
a) not well established
b) adults: 0.03 ug/kg/day
c) infants: 1-5 ug/kg/day
2) warfarin overdose (also see warfarin)
a) vitamin K 1 mg IV in 15-20 mL of normal saline or 2.5-5.0 mg PO for minor bleeding or INR > 9 (fresh frozen plasma for severe bleeding)
b) for INR 5-9, in the absence of bleeding, administration of vitamin K is controversial
Related
coagulation factor IXa
coagulation factor VIIa
coagulation factor Xa
protein C, activated
protein S; vitamin K-dependent protein S (PROS1, PROS)
thrombin; coagulation factor IIa
vitamin K (phytonadione) in serum/plasma
vitamin K deficiency
warfarin (Coumadin, Panwarfin, Jantoven)
Specific
menadione; vitamin K3
phytonadione; vitamin K1; phylloquinone; phytomenadione; methylphytyl naphthoquinone (Mephyton, AquaMephyton)
vitamin K2; menaquinone-4; menatetrenone (INN, MK4)
General
vitamin
Properties
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, American
College of Physicians, Philadelphia 1998
Component-of
alpha tocopherol/ascorbate/biotin/biotin/cobalamin/ergocalciferol/folic acid/multivitamin/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
alpha tocopherol/ascorbate/biotin/cholecalciferol/cobalamin/folic acid/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
calcium carbonate/cholecalciferol/vitamin k
calcium carbonate/vitamin d/vitamin k