Is Nattokinase Interacting With My Warfarin?

Filed Under: Heart Health, Q&As

Is Nattokinase Interacting With My Warfarin?

I know that nattokinase works differently from warfarin. When taking the nattokinase, should we be testing my blood with a test other than PT/INR? I really would like to get off the warfarin, but my pro-time numbers seem to be going the opposite direction from what I had anticipated. Therefore, my doctor keeps increasing my dosage. I am now at 9 mg per day, and I'm noticing more side effects because of it: hair loss, feeling cold all the time, leg pains, taste perversion, gas/bloating. I appreciate all your help.


This is a tough question.

First, as with any supplement—or drug for that matter—not everyone will react the same way when taking nattokinase. Differences may be from biochemical individuality, variation in the product, or interactions with other supplements or drugs (such as warfarin) that are being taken. Here's a short list of supplements that have anti-platelet and/or anticoagulant activity:

  • Garlic
  • Turmeric
  • Vitamin E
  • Fish oil
  • Angelica
  • Danshen
  • Ginger
  • Willow
  • Clove

Of course, the list of drugs that may interact with nattokinase is even longer and ranges from OTC pain-relievers like ibuprofen, naproxen, and aspirin to prescription antibiotics, anti-ulcer medications, and other blood thinners such as heparin and Plavix.

Any time you try to replace a drug with a supplement, the prudent thing is to do it under the guidance and direction of a skilled health professional. I'm not aware of clinical studies that have focused on dosages or detailed methods of even trying to switch from warfarin to nattokinase.

Typically, nattokinase will potentiate warfarin, which results in lowered INR values—but again, that would need to be confirmed in your particular case. As I've discussed previously, nattokinase works similar to plasmin (and actually increases the body's production of plasmin) by helping to dissolve fibrin. It also addresses blood coagulation to some extent.

Realistically, to determine if nattokinase will achieve the effects your doctor is trying to accomplish in your case, gradually adding a small dose of high-quality nattokinase to your regimen and monitoring the results is the only thing I can suggest.

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DISCLAIMER: The content of is offered on an informational basis only, and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified health provider before making any adjustment to a medication or treatment you are currently using, and/or starting any new medication or treatment. All recommendations are "generally informational" and not specifically applicable to any individual's medical problems, concerns and/or needs.

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