Therapy Information

Important Points For Oral Anticoagulant Use

Why is warfarin (Coumadin) prescribed?

Warfarin is an anticoagulant("blood thinner") and it helps to prevent harmful blood clots from forming or getting larger.

When and how should warfarin be used?

  • Take as a single dose, at the same time each day, every 24 hours, preferably in the evening.
  • If a dose is missed, do not double the dose the next day.
  • Take warfarin only as prescribed. Do not adjust the dose.
  • Warfarin comes in several different colors, each color represents a different strength tablet.

What special instructions should be followed?

  • The prothrombin time(PT) is the test used to measure the time it takes the blood to clot.
  • The warfarin dose is adjusted based on the International Normalized Ratio (INR) which is calculated based on the PT result.
  • Faithfully keep appointments to have PT done.
  • Avoid activities that have a high injury risk.
  • Wear a medical alert bracelet/carry an anticoagulant ID card.
  • Avoid aspirin and aspirin containing products.
  • Avoid drug interactions. Check with your pharmacist before taking other medications.

What special dietary instructions should be followed?

  • Do not change dietary habits without speaking to anticoagulation service personnel.
  • Do not eat large amounts of green leafy vegetables and Vitamin K rich foods.
  • Avoid heavy use of alcoholic beverages.

What complications should be reported?

  • Nose bleeds, bruising, bleeding gums, vomiting or spitting up of blood or brown material resembling coffee grounds.
  • Bloody or black tarry stools, bloody or dark brown urine.
  • Heavy menstrual bleeding.
  • Vomiting, diarrhea, loss of appetite, fatigue, fever, chills, sore throat, mouth sores, rash, itching, unexpected pain such as headaches, stomach pain or backaches.

Other precautions

  • Notify the doctor or nurse immediately if you become pregnant while on warfarin.
  • Inform the doctor or dentist before any procedures, that you are taking warfarin.
  • If planning a trip, have your PT checked before leaving, take medical information and warfarin with you.