New Health Condition: What does that mean for INR & warfarin?

Publication Date: 
Fri, 09/06/2013
By: Alere Staff

When diagnosed with a new health condition, it is important to keep in mind the potential effect this may have on your warfarin therapy. New medications, health conditions, and dietary changes can impact your INR (International Normalized Ratio).1 Always make sure both your doctor managing your warfarin and the treating physician of the new health condition have a complete, up-to-date list of all of your medications. Don’t assume this information will get communicated any other way.

Below are just a few of the conditions and treatments that may impact your INR level and warfarin dose requirements.2

  ●  Thyroid disease   ●  Diabetes
  ●  Congestive heart failure   ●  Liver disease     
  ●  Kidney disease   ●  Cancer
  ●  Fever   ●  Diarrhea

Treatment is needed for all of your health conditions. Be prepared to test your INR more frequently during this time until your INR becomes stable again. By clearly communicating all changes in your health to all of your doctors, adjustments in therapy can be made, along with careful monitoring to help prevent any complications or problems.

Home INR monitoring will help improve your control of warfarin. Studies have shown that increasing testing frequency with weekly testing of INR improves patient safety and helps keep the drug in its therapeutic effective zone .3,4 Weekly testing was shown to be the most effective testing frequency.5 Go to the Getting Started page or call Alere at 1.800.504.4032 for more information about testing your INR at home.

  1. Demirkan, K., et al. Response to Warfarin and Other Oral Anticoagulants: Effects of Disease States. South Med J. 2000;93(5).
  2. Ansell, J., Oertel, L., Wittkowsky, A. Managing Oral Anticoagulation Therapy: Clinical and Operational Guidelines 3rd Ed. Lippincott Williams & Wilkins. Philadelphia, PA. 2009.
  3. Am J Manag Care. 2014;20(3):202-209.
  4. Heneghan C., et al. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. 2006. Lancet, 367, 404-11.
  5. Center for Medicare and Medicaid Services. Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management  (CAG-00087R) [Memorandum]. 2008. Baltimore, MD.