Phytonadione

Vitamin K/Nutrient Depletion:

  • AntacidsAntacids: Based on the mechanism of action, high doses of antacids may decrease absorption of fat-soluble vitamins such as vitamin K. Clinical evidence is lacking.
  • AntibioticsAntibiotics: Vitamin K is synthesized by bacteria in the human gut. Since some antibiotics (such as broad-spectrum antibiotics) may decrease bacteria in the human gut, they may lower vitamin K levels and increase the risk of deficiency in people not ingesting adequate amounts. Clinical evidence is lacking.
  • AnticonvulsantsAnticonvulsants: Vitamin K deficiency has been reported in patients treated with anticonvulsants and in infants of mothers taking anticonvulsants (82; 83; 84).
  • AntilipemicsAntilipemics: Replacement of long-chain triglycerides with medium-chain triglycerides/long-chain triglyceride lipid emulsion resulted in a decrease in plasma vitamin K1 levels (87). Based on the mechanism of action, cholestyramine (Questran?) mineral oil may decrease the absorption of oral vitamin K and increase vitamin K requirements. Clinical evidence is lacking.
  • DactinomycinDactinomycin: Based on the mechanism of action, dactinomycin, a cancer chemotherapy drug, may decrease the effects of vitamin K and increase vitamin K requirements. Clinical evidence is lacking.
  • IsoniazidIsoniazid: Case reports exist of vitamin K deficiency in patients treated with rifampin and isoniazid (107; 108).
  • OrlistatOrlistat: Based on the mechanism of action, orlistat may decrease vitamin K absorption. Clinical evidence is lacking.
  • QuininesQuinines: Based on the mechanism of action, quinine, or quinidine, may increase vitamin K requirements. Clinical evidence is lacking.
  • RifampinRifampin: Case reports exist of vitamin K deficiency in patients treated with rifampin and isoniazid (107; 108).
  • SalicylatesSalicylates: In vitro, salicylates have been shown to antagonize vitamin K metabolism (109).
  • TiratricolTiratricol: Based on the mechanism of action, tiratricol (a drug not available in the United States) may decrease vitamin K absorption. Clinical evidence is lacking.