Over The Counter (OTC) and Herbal Medicine Interactions with Warfarin

Over The Counter (OTC) and Herbal Medicine Interactions with Warfarin

  • 10 Mar 0

Warfarin can change the way other medicines work and other medicines can also change the way warfarin works. It is very important to inform your anti-coagulation provider about all other medicines that you are taking, including other prescription medications, over-the-counter medicines, nutritional supplements, or herbal products. Reading nutritional labels is very important for warfarin users and should be done with every product you take.

Non-Prescription Pain Medicines:

Medications you can use:
• Acetaminophen (Tylenol®): no more than 2000mg per day
= 6 – 7 regular strength 325mg tablets
= 4 extra strength 500mg tablets
Medications to avoid:
• Ibuprofen (Advil®, Motrin®, Nuprin®)
• Naproxen (Aleve®, Anaprox®, Naprosyn®)
• Aspirin (Ecotrin®, Bayer®), unless prescribed by your doctor
• Other products that may contain aspirin or aspirin-like products: Excedrin®, Alka-Seltzer®, Pepto-Bismol®

Vitamin K-Containing Products:

Multi-vitamins that have vitamin K are OK as the content is usually less than 50mcg of Vitamin K. However, they should be taken consistently and be sure to check your labels as it can vary from product to product.

Two Viactiv® calcium chews (the recommended daily dose) contain 80mcg of vitamin K—for some, this may be a significant amount of vitamin K and you may find a dramatic impact on the INR requiring a warfarin dose increase.

Ensure®, energy bars and other similar meal supplements contain varying amounts of vitamin K very much like a well-balanced meal would. Be sure to report any significant change in the consumption of these products to your provider.

Herbal Products

Products that should generally be avoided due to the risk of warfarin interaction or increased bleeding, unless specifically recommended by your doctor:
• Danshen
• Garlic (high potency supplement—garlic in your food is not a problem)
• Ginkgo
• Ginseng
• Fish oil
• Kava kava
• Omega-3 fatty acids
• Turmeric
• Vitamin E

Products that may interact, but can usually be taken with closer monitoring of the INR after initiation include:
• Coenzyme Q10
• Green tea (if very large quantities–i.e. a gallon–are consumed)
• Soy products
• St. John’s Wort
Last modified on Monday, 10 March 2014

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