Some studies found a negative correlation between vitamin K intake and INR changes, while others suggested that a minimum amount of. Summary. Little study has been performed on the effect of vitamin K intake on the variability of warfarin's anticoagulant effects over long period of time. How much effect does the vitamin K content of green leafy vegetables have on prothrombin time/international normalized ratio (INR) results?.
Conclusion No significant association was observed between usual vitamin K intake and anticoagulant effects.
Vitamin K and PT/INR results
Further studies are required to consider inter-individual variability of vitamin K intake. Development of assessment tools to measure inter-individual variability of vitamin K intake might be helpful. Footnotes Conflict of Interest: The authors have declared no conflict of interest. Savelieva I, Camm J. Update on atrial fibrillation: Prevalence of and risk factors for atrial fibrillation in Korean adults older than 40 years. J Korean Med Sci. Mechanism of action, clinical effectiveness, and optimal therapeutic range.
Anticoagulation intensity and outcomes among patients prescribed oral anticoagulant therapy: The pharmacology and management of the vitamin K antagonists: Curr Opin Mol Ther. Role of dietary vitamin K intake in chronic oral anticoagulation: Compilation of a provisional UK database for the phylloquinone vitamin K1 content of foods.
Vitamin K and Warfarin: What You Should Know
Interactions of warfarin with drugs and food. Warfarin and vitamin K intake in the era of pharmacogenetics.
Br J Clin Pharmacol. High usual dietary vitamin K intake is associated with low relative variability in vitamin K intake: Patients with unstable control have a poorer dietary intake of vitamin K compared to patients with stable control of anticoagulation.
Association Between Usual Vitamin K Intake and Anticoagulation in Patients Under Warfarin Therapy
Relationship between dietary vitamin K intake and the stability of anticoagulation effect in patients taking long-term warfarin. Dietary vitamin K intake and anticoagulation control during the initiation phase of warfarin therapy: A study on the relationship between drug related knowledge, sick role behavior and quality of life of patients taking warfarin.
In doing so, vitamin K plays a role in your body's natural clotting process.
Warfarin works against vitamin K. Specifically, warfarin reduces your liver's ability to use vitamin K to produce normally functioning forms of the blood clotting proteins.
By reducing the liver's ability to use vitamin K to produce normally functioning forms of the blood clotting proteins, warfarin reduces your risk of forming a blood clot. So how does my intake of vitamin K affect my warfarin therapy?
A significant change in your intake of vitamin K can result in a significant, and potentially dangerous, change in your INR. For example, if you reduce the amount of vitamin K in your diet, your INR will increase.
- Association Between Usual Vitamin K Intake and Anticoagulation in Patients Under Warfarin Therapy
Also, reducing the amount of vitamin K in your diet may make it more difficult to manage your warfarin therapy. Patients who have a low intake of vitamin K have been found to have more fluctuation in their INR, which is the test used to measure the effect of warfarin and to adjust the dose of warfarin. Why would a diet low in vitamin K make my INR more difficult to manage? Suppose you have a diet that is extremely low in vitamin K. Now suppose you eat a spinach salad at dinner one night.
Most studies included patients with various indications for VKAs therapy, such as atrial fibrillation, prosthetic heart valves, and venous thromboembolism. Thus, INR target was dishomogeneous and no subanalyses for specific populations or different anticoagulants were conducted. Measures used to evaluate anticoagulation stability were variable.
Vitamin K and Warfarin (Coumadin): What You Should Know - ClotCare
The available evidence does not support current advice to modify dietary habits when starting therapy with VKAs. Restriction of dietary vitamin K intake does not seem to be a valid strategy to improve anticoagulation quality with VKAs.
It would be, perhaps, more relevant to maintain stable dietary habit, avoiding wide changes in the intake of vitamin K. This assumption was one of drivers for the development and introduction of the non-VKA oral anticoagulants NOACs, previously referred to as new or novel oral anticoagulants 7 which directly inhibit thrombin such as dabigatran 8 or factor Xa such as rivaroxaban, apixaban, and edoxaban, 9 — 11 for the treatment of AF and VTE.