Drug Interactions
Dandelion Greens & Warfarin
PTINR.com Staff
Salads rich in dandelion greens may actually increase your INR test results despite their rich green color.
Spring is a time for change. More fruits and vegetables are chosen over heavier pastas and carbohydrate comfort foods. Salads become a popular choice as the weather warms and you spend more time outside. Salads often include a variety of leafy greens, which contain moderate to high amounts of vitamin K. Vitamin K, in large quantities can reduce the effectiveness of Coumadin®* and lower INR test results. Patients are often told to keep their portion sizes consistent and avoid large increases or decreases in leafy greens to maintain stable INR blood test results.1 Not all leafy greens however lower INR test results – dandelion leaves are a good example.
Dandelion leaves are popular in salads, soups and even wines. Despite their dark green leaf color, dandelion leaves contain properties that can actually increase INR test results. Dandelion leaves contain coumarins, a natural anticoagulant, that can interfere with platelet function. 1 Platelets play a key role in normal blood clotting.
Enjoy your salads in moderation. As a general rule, the darker the green of your vegetables, the higher the vitamin K content in them and the greater the effect on lowering your INR test results. Dandelion greens may have the opposite effect on your test results. Remember to keep all your scheduled clinic appointments and keep track of your vitamin K intake.
More frequent patient self-testing can identify food interactions and INR drift or decline sooner than patients who test their blood less often. In addition, testing at home allows you to increase your frequency of testing and detect any unexpected or surprise food interactions that may result – like that of dandelion leaves. Studies have shown less fluctuation in INR test results 2 and better INR control and safety for those patients who test weekly. 3
For more information on the vitamin K content in your foods, visit our Vitamin K Registry. We have assembled more than 1000 choices of foods and beverages for your reference.
*Coumadin® is a registered trademark of Bristol-Myers Squibb Pharma Company.References:
1 Bristol-Myers Squibb Company. (2009). Medication Guide for Coumadin Tablets and Coumadin for Injection [Package Insert]. Princeton, NJ: Bristol-Myers Squibb Company.
2 Center for Medicare and Medicaid Services. (2001). Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management, (CAG-00087C) [Memorandum]. Baltimore, MD.
3 Heneghan C., et al. (2006). Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet, 367, 404-11.