Warfarin was discontinued and the patient received a vitamin K supplementation and transfusions. At day 5, the biological assessment revealed an anemia with an hemoglobinemia of 5.1 g/dL and an International Normalized Ratio (INR) of 7.3, indicating a Vitamin K Antagonist (VKA) overdose. At day 3, he reported faintness and melena. He was also treated with warfarin for atrial fibrillation.

A patient over 75 years old was treated with nab-paclitaxel and gemcitabine a first course for a metastatic pancreatic adenocarcinoma (day 0). This case reports drugs interactions leading to bleeding secondary to warfarin overdose. Some patients are adept at taking medicinal plants, a practice often unknown to health professionals who take care of it. Patients don't necessarily mention to their oncologist this phytotherapeutic treatment which may be responsible for unsuspected drug interactions. Mistletoe, Viscum album, is a medicinal plant used in complementary medicine in oncology. These findings provide new insights into selectively controlling the physiological and pathological processes involving electron transfers mediated by vitamin K and ubiquinone. Intriguingly, dihydroorotate dehydrogenase, another ubiquinone-associated ferroptosis suppressor protein parallel to the function of FSP1, does not support vitamin K-dependent carboxylation. FSP1 inhibitor that inhibited ubiquinone reduction and thus triggered cancer cell ferroptosis, displays strong inhibition of vitamin K-dependent carboxylation. We find that ferroptosis suppressor protein 1 (FSP1), a ubiquinone oxidoreductase, is the enzyme responsible for vitamin K reduction in a warfarin-resistant manner, consistent with a recent discovery by Mishima et al. Here, we report the identification of warfarin-resistant vitamin K reductase using a genome-wide CRISPR-Cas9 knockout screen with a vitamin K-dependent apoptotic reporter cell line. Despite the functional discovery of vitamin K reductase over eight decades ago, its identity remained elusive. Patients overdosed on warfarin can be rescued by administering high doses of vitamin K because of the existence of a warfarin-resistant vitamin K reductase. Warfarin, a vitamin K antagonist, is the most commonly prescribed oral anticoagulant.

Vitamin K is a vital micronutrient implicated in a variety of human diseases.

Antidote for vitamin k overdose