The availability of vitamin K is affected by a variety of dietary and drug-related factors.


Vitamin K is fat-soluble and light sensitive (which may reduce levels in unshielded TPN solutions).


Factors interfering with vitamin K absorption:

(1) pica

(2) ingestion of mineral oil

(3) cholestyramine

(4) large oral doses of vitamin A


Factors interfering with enteric production of vitamin K by bacteria:

(1) antibiotics


Factors interfering with vitamin K metabolism (antagonists):

(1) therapy with coumarin/warfarin

(2) coumarin-like compounds in herbal medications or plants

(3) aspirin in large doses

(4) phenytoin

(5) large doses of vitamin E


To read more or access our algorithms and calculators, please log in or register.