What is Coumadin/Warfarin?

Coumadin/Warfarin is an anticoagulation medication (blood thinner) prescribed to to prevent heart attacks, strokes and blood clots in veins, arteries and lungs. It treats or prevents clots that may occur because of a type of abnormal heart beat (atrial fibrillation) or heart valve replacement. Many of our patients require anticoagulation therapy so we work closely with you, your cardiologist and your primary care provider to make sure all of your medications are working together to address your condition.

Coumadin/Warfarin begins to reduce blood clotting within 24 hours after taking the first dose. However, the full effect may take 3-5 days or longer to occur. During this time, you may need to be treated with Lovenox injections or IV heparin until the medicine is in full effect.

Important reminders about anticoagulation therapy

  • Notify all of your physicians, dentist and pharmacist that you are taking Coumadin/Warfarin.
  • Carry an ID card or consider wearing a medical alert bracelet.
  • Moderate exercise and activity are safe for most people taking Coumadin/Warfarin. Avoid any activity or sport that may result in traumatic injury.
  • If you need surgery, call your doctor that is monitoring your INR levels. The surgeon or dentist may want to hold your Coumadin/Warfarin before a procedure. Some people may need to take another anticoagulant in the meantime.
  • If you are planning to travel, let your physician know before your trip. You may need to make plans for INR checks. You should also carry your medicines with you at all time. Luggage may get lost and drugs left in cars may degrade in extreme heat or cold.
  • Acute illness can change your response to Coumadin/Warfarin. Please let your physician know if you have these symptoms:
    • Nausea or vomiting
    • Diarrhea
    • Severe flu-like symptoms
    • Started on an antibiotic


Frequently Asked Questions

How well anticoagulants work varies from person to person. Remember, for best results, consistency is important. Based on your diagnosis, your physician will set a target range to gauge how long it takes for your blood to clot.

  • Your level will be monitored by an blood test called an INR (International Normalized Ratio)
  • You will need to be tested 2-3 times per week when you first start this medication. Once your INR level becomes more consistent, you will be able to have in checked once a month. Do not miss any scheduled blood draws and never go more than 30 days without having it checked.
  • After you have your INR drawn, you will be contacted by our office within 24 hours if changes need to be made to your dose.
  • Medication changes or starting new medications (especially antibiotics, pain medicine, steroids and/or cough medicine) can alter your INR level. Over the counter products and herbal supplements can also affect your INR. Please inform any physician that prescribes new medicine that you are also taking Coumadin/Warfarin.
  • Consistency is important. Always take your Coumadin/Warfarin at the same time each day, preferably in the evening or at least 15 hours before having your blood drawn. You may take it with our without food.
  • Never skip a pill. If you miss a dose, take it as soon as you remember that day. However, if it is the next day, do not double up; just take your scheduled dose.
  • Notify the office if you miss 2 or more doses.
  • Acute illness can affect your INR levels as well
  • Avoid smoking completely

Foods high in vitamin K decrease the effectiveness of Coumadin/Warfarin. You can eat foods with vitamin K, just be consistent and eat the same amount daily.

Foods high in vitamin K should be limited to 1 serving a day

  • Kale, boiled, ½ cup
  • Spinach, boiled, ½ cup
  • Turnip greens, boiled, ½ cup
  • Collard greens, boiled, ½ cup
  • Swiss chard, boiled, ½ cup
  • Parsley, raw, ¼ cup
  • Mustard greens, boiled, ½ cup

Foods moderately high in vitamin K should be limited to 3 servings a day

  • Brussel sprouts, boiled, ½ cup
  • Spinach, raw, 1 cup
  • Turnip greens, raw, 1 cup
  • Green leaf lettuce, raw, 1 cup
  • Broccoli, raw, 1 cup
  • Endive, raw, 1 cup
  • Romaine lettuce, raw, 1 cup

Avoid sudden or frequent changes in your diet. Avoid drinking alcohol which can increase some side effects of Coumadin/Warfarin. For special occasions, limit to 1 alcoholic drink (1 drink = 1 glass of wine = 1 cocktail/shot).

Minor Bleeding

  • Gum bleeding while brushing teeth
  • Occasional nose bleed
  • Easy bruising
  • Prolonged bleeding after minor cuts
  • Prolonged menstrual bleeding

You may notice any of the symptoms from time to time. If you are unsure whether bleeding is significant, call your doctor. You may need to have your INR checked.

Major Bleeding

  • Red or dark brown urine
  • Red or black tarry stool
  • Vomiting up blood or material that looks like coffee grounds
  • Coughing up blood
  • Severe headache or stomach ache
  • Unexplained bruising
  • Frequent nose bleeds, bleeding gums or unusual bleeding
  • Unexplained or excessive bleeding that doesn’t stop after 10 or 15 minutes

If you have a serious fall or you hit your head, call your physician and or go to your nearest emergency room right away.

  • Blood clotting
  • Sudden weakness, numbness, or tingling in any limb
  • Visual changes or loss of sight in either eye
  • Sudden onset of slurred speech or inability to speak
  • Dizziness or faintness
  • New pain, swelling, redness or heat in extremity
  • New shortness of breath or chest pain