These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A study of factors which determine the pharmacological response to vitamin K in coumarin anticoagulated rabbits.
    Author: Hart JA, Haynes BP, Park BK.
    Journal: Biochem Pharmacol; 1984 Oct 01; 33(19):3013-9. PubMed ID: 6487353.
    Abstract:
    The pharmacological response to vitamin K has been determined by measuring prothrombin complex activity (P.C.A.) in male New Zealand White rabbits anticoagulated (P.C.A. less than 20%) with the long acting 4-hydroxycoumarin brodifacoum, at a dose (10 mg/kg) which produces maximum antagonism of vitamin K1. Thus, according to current concepts, this animal model may be used to assess vitamin K requirements in the absence of a functional vitamin K-epoxide reductase. After intravenous administration of vitamin K1 (1 mg/kg) P.C.A. reached a maximum (64 +/- 19%) at 3 hr and then declined at a rate which corresponds to complete inhibition of clotting factor synthesis. Vitamin K2 (1 mg/kg) stimulated clotting factor synthesis for 2 hr, while cis-vitamin K1, vitamin K3, vitamin K1 2,3-epoxide and oral administration of vitamin K1 were ineffective. Plasma concentrations of vitamin K1 fell steeply during the 12 hr following administration of a pharmacological dose, and then declined with a terminal half-life of 18.9 +/- 9.0 hr. Comparison of the pharmacodynamic and pharmacokinetic data indicated that plasma concentrations in the range 0.4-1.0 microgram/ml are required for clotting factor synthesis in the limiting situation of maximum antagonism of vitamin K by coumarin anticoagulants. These findings explain why frequent and repeated administration of vitamin K1 may be necessary during coumarin poisoning.
    [Abstract] [Full Text] [Related] [New Search]