Warfarin (Cofarin) is one of the commonly used anticoagulant drugs clinically. It is commonly used to treat and prevent thrombotic diseases such as venous thrombosis, pulmonary embolism, embolic stroke and after heart valve replacement. Dosage will vary from person to person. Doctors will take blood to monitor coagulation time to adjust the appropriate dosage. Patients should not stop or increase or decrease the dosage without authorization.

Strengthen anticoagulation

For example: Ginkgo biloba, Ganoderma lucidum, garlic, angelica, fish oil (> 2 g/day), linoleic acid, vitamin E (> 400 IU/day), mango, grapefruit, cranberry, pomegranate(juice), onion, chilies, ginger powder, grape carbohydrate amine (> 500 mg/day) and so on, may cause the risk of bleeding if combined with drugs.

Reduce anticoagulation

• For example, vitamin K, high-dose vitamin C, coenzyme Q10, St. John's wort, licorice, green tea (catechin), ginseng, etc., may reduce the effect of anticoagulants.
• Others: Norni juice reduces the efficacy of warfarin, and the mechanism is unclear.

Warfarin and vitamin K

There are many coagulation factors in the body, among which the 2nd, 7th, 9th and 10th coagulation factors must be activated by active vitamin K to exert coagulation function. The effect of warfarin is to reduce the active vitamin K in the body, so that the coagulation factor cannot be activated to achieve the anticoagulation effect. Therefore, high intakes of vitamin K in foods can weaken the effects of warfarin.

Vitamin K content in food

(In principle, no special avoidance is required, but fixed amounts should be maintained)

If you have any questions, please consult a dietitian!

References:

• Drug - nutrition interactions: Coumadin and vitamin K. Warren Grant Magnuson Clinical Center, National Institutes of Health.
• Booth SL. Vitamin K: food composition and dietary intakes. Food & nutrition research 2012;56.
• Booth SL, Suttie JW. Dietary intake and adequacy of vitamin K. The Journal of nutrition 1998;128(5):785-8.