Possible Interaction: Phenprocoumon and Vitamin K

“2) In sheep vitamin K counteracts the effect of phenprocoumon on the blood coagulation system, but not that on the osteocalcin production.”

“dosages of antithyroid drugs, as it was the case in our patient (methimazole 80 mg daily; usual maintenance dose: 5–… in a previously reported patient (propylthiouracil 1000 mg daily; usual maintenance dose: 100–150 mg daily), and concomitant use of vitamin K … phenprocoumon , appear to be …-induced coagulation derangements.”

“SummarySuccessful prevention of the progression of incipient hemorrhagic skin necrosis by timely administration of vitamin K1 in a woman treated with phenprocoumon is presented.”

“Both patients developed a serious increase in hypocoagulability, requiring administration of phytomenadione and temporary decreases in phenprocoumon dose.”

“From the experiments it is concluded that (1) PHY inhibits the action of PPC without influencing its pharmacokinetics, and (2) that PPC distinctly changes the pharmacokinetics of PHY and diminishes its pharmacodynamic action as measured by changes in the prothrombin complex activity.”

“Following pretreatment with phenprocoumon and after intravenous administration of vitamin K1, both the average half-life and area under the plasma concentration-time … detectable in plasma and the half-life of the epoxide was 13.8 h. Based on area considerations the data suggest that either phenprocoumon … vitamin K1, ….”