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College of Pharmacy

HelixTalk Episode #121 - But Wait, There’s More! Unusual Warfarin Interactions

Date posted: November 3, 2020, 6:00 am

In this episode, we will discuss some of the interesting and unusual warfarin interactions such as acetaminophen, alcohol, agents with antiplatelet properties, non-green vitamin K foods, and CBD/THC.

Key Concepts

  • Patients should always be educated to consult their pharmacist and/or PCP whenever there is a change in any medications (OTC, prescription, herbals, supplements, etc.) as well lifestyle (diet, weight loss, alcohol use, THC use, etc.)
  • Closer monitoring of INR is required in most instances of warfarin drug interactions; some interactions do not modify the INR but can still increase the risk of bleeding/bruising
  • A warfarin interaction rarely means "contraindication". Warfarin dose adjustment may address the INR fluctuations but in some cases stopping the use of such products becomes necessary.

References

  1. Foods with Vitamin K. http://www.coumadin.bmscustomerconnect.com/servlet/servlet.FileDownload?file=00Pi000000bxvTFEAY
  2. Coumadin Package Insert. http://www.coumadin.bmscustomerconnect.com/servlet/servlet.FileDownload?file=00Pi000000bxvTFEAY