Chamomile & Warfarin
Chamomile is one of the most commonly used medicinal herbs and has been recognized for its therapeutic properties since the age of Hippocrates. Some traditional remedies include: treatment for bronchitis, fever, liver and gallbladder concerns. Chamomile also has been used historically for digestive ailments, relaxation and reported to be effective for treating eczema.1
Chamomile, a member of the daisy family, is commonly used in tea and available in dietary supplements such as tablets, capsules and ointments.
Interaction with Warfarin
Despite widespread use and overall familiarity as an herb - chamomile is considered to have a moderate drug interaction with warfarin. Use of chamomile with warfarin has been shown to increase the potency of warfarin resulting in an increased INR test results.2 An increase in your INR means the time it takes your blood to form a clot increases.
Signs of over anticoagulation and possible interaction with chamomile include bleeding or excessive bruising. As always before changing your diet or taking natural supplements, speak with your doctor before starting or stopping chamomile in any form.2
Increasing testing frequency is recommended when starting or stopping any new medication or dietary supplement including vitamins. Home INR monitoring will help improve your control of warfarin. More frequent testing, typically performed by patient self testing, is a valuable tool for detecting rises and falls in INR values and enable you to work with your clinician to make any adjustments to diet or medication dosing.3
- Blumberg, J. B., McKay, D. L., A Review of the bioactivity and potential health benefits of chamomile tea (Matricaria recutita L.). Phytother. Res. Vol 20, Issue 7. 2006.
- Bristol-Myers Squibb Company. Medication Guide for Coumadin Tablets and Coumadin for Injection [Package Insert]. Princeton, NJ: Bristol-Myers Squibb Company. 2009.
- Center for Medicare and Medicaid Services. Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management (CAG-00087R) [Memorandum]. Baltimore, MD. 2008.