Will phytonadione interact with my other medicines?

Phytonadione may interact with several medicines. Drugs that prevent clotting, such as warfarin (Coumadin), may not work as well if you are also taking vitamin K. The weight-loss medicine called orlistat (Alli, Xenical) may decrease the concentration of vitamin K, because orlistat decreases the absorption of certain vitamins, including vitamin K. Finally, mineral oil may decrease the amount of phytonadione that your body can absorb, so if you are taking both of these medicines, your doctor should monitor you to make sure you are getting the right dose of phytonadione.