PHYSIOLOGIC ROLE OF VITAMIX K 771 



counteracted by ^'itamin Ki or by vitamin Ki oxide, which is usually given 

 intravenously as an emulsion. The results with menadione and with the 

 simpler vitamin K-active compounds have been less convincinjT. Mena- 

 dione and Synkovil are considered to have only a slight effect against anti- 

 coagulants such as the dicumarol group, '**''~'^^ although menadione bi- 

 sulfite has been reported to be as effecti\'e when administered intrave- 

 nously'*^"'*^ as it is intramuscularly and orally.'^" Oeill and co-workers'^' 

 reported that doses of 10 to 20 mg. of vitamin Ki given intravenously in 

 the form of a sterile aqueous colloidal solution are recommended as a 

 means of raising the proconvertin-prothrombin \'alue in cases in which 

 treatment with dicumarol anticoagulants has resulted in serious hemor- 

 rhage. Higher doses were found to be unnecessary, and were dangerous in 

 that they increased the incidence of thrombosis. Menadione as such was 

 of no value in counteracting the hypoprothrombinemia caused by the 

 dicumarol anticoagulant. 



(3) Miscellaneoics Effects of Vitamin K 



In addition to counteracting the effect of anticoagulants in which it 

 acts as a stimulant to prothrombin production, vitamin K has been found 

 to reduce the hemorrhagic tendency occurring when a condition of hyper- 

 vitaminosis A obtains. Light, Alscher, and Frey'^- reported that this 

 defect in clotting responds to treatment with vitamin K. It is not certain 

 what the mechanism is by which vitamin A produces the hemorrhagic 

 tendency. 



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