Vitamin K toxicity Domina Petric, MD

Vitamin K toxicity Phylloquinone exhibits no adverse effects when administered in massive doses by any route. The menaquinones are similarly thought to have negligible toxicity.

Vitamin K toxicity Menadione can be toxic. At high doses, it can produce hemolytic anemia, hyperbilirubinemia and severe jaundice.

Vitamin K toxicity Phylloquinone has replaced menadione for the vitamin K prophylaxis of neonates. The intoxicating doses of menadione appear to be at least three orders of magnitude above those levels required for normal physiological function. At such high levels, menadione appears to produce oxidative stress.

Vitamin K toxicity The vitamer menadione is undergoing monovalent reduction to the semiquinone radical. In the presence of O2 it is reoxidized to the quinone, resulting in the formation of the superoxide radical anion. High levels of menadione are known to react with free sulfhydryl groups, thus depleting reduced glutathione (GSH) levels.

Literature Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008.