Is it okay to take multivitamins with warfarin?
It would be okay for you to take a multivitamin while on warfarin. However, you should choose one that does not contain vitamin K, such as One-A-Day and Shaklee Formula 1. Warfarin interferes with the liver synthesis of vitamin K dependent clotting factors (II, VII, IX, X) and causes the blood to become “thinner.” This makes the International Normalized Ratio (INR) increase and puts the patient at risk for bleeding problems. Vitamin K promotes the liver synthesis of clotting factors and increases the coagulation effects of the blood. This causes the INR to decrease and makes the blood “thicker,” putting the patient at risk for forming blood clots. Vitamin K antagonizes the effects of warfarin, which leads to decreased anticoagulation. Multivitamins that contain vitamin K should be avoided due to the interaction with warfarin. It is very important to contact your physician before starting or stopping vitamins that contain vitamin K so that the warfarin dosage can be adjusted according t
