What should I know when taking warfarin?

Joaquin Solis, MD
Cardiology (Cardiovascular Disease)

If you are taking warfarin (Coumadin, Jantoven) -- an anticoagulant ("blood thinner") that prevents harmful blood clots from forming:

  • You will need a blood test regularly to check how the drug is working and if the dose is right for you. This test is called INR, or international normalized ratio. It will be done often when you first start taking the drug. Once the right dose is determined, the test is done less often.
  • Avoid activities in which you are at risk for causing bleeding.
  • You may want to carry a card or wear a bracelet that says you take warfarin. That way, people treating you if you ever have an accident will know you take this drug.
  • Ask your doctor how much, if any, alcohol you can safely have (beer, wine, liquor).
  • Do not increase or decrease your intake of foods with vitamin K (for example, green, leafy vegetables) without talking to your doctor.
  • Do not get body piercings or tattoos while taking this drug. Always discuss this with your doctor.
  • Check your supply of warfarin before vacations, holidays, and other times when you might not be able to get it.
  • Do not stop taking warfarin without talking to your doctor.
  • Do not let anyone else take your medicine.