vitamin K

Pharmacology

• warfarin inhibits synthesis of vitamin K-dependent coagulation factors (II, VII, IX & X)

Physiology

• cofactor in post-translational modifications by vitamin-K dependent carboxylase
  • coagulation factors II, VII, IX & X
  • protein C is a vitamin K dependent serine protease
  • protein S is a vitamin K-dependent binding protein
• results in amino terminal gamma-carboxyglutamate residues
• negatively charged gamma-carboxyglutamate bind Ca+2 & mediate adherence of coagulation factors to the surface of activated platelets

Dosage

• Minimum daily requirements:
  • not well established
  • adults: 0.03 ug/kg/day
  • infants: 1-5 ug/kg/day
• warfarin overdose (also see warfarin)
  • 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)
  • for INR 5-9, in the absence of bleeding, administration of vitamin K is controversial

More general terms

• vitamin

More specific terms

• menadione; vitamin K3
• phytonadione; vitamin K1; phylloquinone; phytomenadione; methylphytyl naphthoquinone (Mephyton, AquaMephyton)
• vitamin K2; menatetrenone (INN, MK4)

Additional terms

• 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 deficiency
• warfarin (Coumadin, Panwarfin, Jantoven)

Component of

• calcium carbonate/vitamin d/vitamin k
• alpha tocopherol/ascorbate/biotin/cholecalciferol/cobalamin/folic acid/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
• alpha tocopherol/ascorbate/biotin/biotin/cobalamin/ergocalciferol/folic acid/multivitamin/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
• calcium carbonate/cholecalciferol/vitamin k