Warfarin and Monitoring Your INR

Contact Information

(608) 263-8475

The University of Wisconsin Anticoagulation Services program works with patients to administer the proper dosage of Warfarin sodium, a drug that is often referred to as a blood thinner. Our goal is to administer the lowest effective dose and maintain the target international normalized ratio (INR).


What does Warfarin do?


Warfarin, like all blood thinners, helps prevents blood clots, which may form in patients being treated for:

  • Stroke
  • Atrial fibrillation
  • Heart failure
  • Heart valve replacement
  • Deep vein thrombosis
  • Pulmonary embolism 

Warfarin and Your INR


Since there is no standard dose for Warfarin, it must be monitored to know if it is working effectively and safely for you. Monitoring is done through the INR blood test.


Sometimes it may seem like your INR result is always changing. There are many things that can cause the number to be high or low.


Stabilizing Your INR


Here are some tips on how you can help keep your INR number as stable as possible:

  • Take your Warfarin exactly as prescribed
  • Take your Warfarin dose at the same time every day
  • Never double a dose for a missed dose
  • Keep all scheduled visits or call promptly to reschedule
  • Tell your health care provider if you start any new medication
  • Tell your health care provider before you start any over-the-counter product or dietary supplement
  • Eat a consistent diet
  • Maintain the same number of servings and the same serving sizes of vitamin K foods each week
  • Avoid alcohol
  • Keep your activity level the same and tell your health care provider if you plan to increase or decrease your activity level