Your doctor wants you to take warfarin for
Your INR target range
Your warfarin manager is
Phone number _____________________________________
Table of Contents:
Topic Page Number
Take home points 2
Warfarin dosing and monitoring 3
Interactions with other medications 7
How lifestyle changes could affect the INR 8
How diet affects the INR 9
Signs of a blood clot and stroke 11
Vitamin K food content list 12
Stopping anticoagulation for procedures 13
Quiz questions 14
Emergency pocket card 16
Web Based Resources:
UW Health - Anticoagulation Services
Clot Care Online Resource
National Blood Clot Alliance
Take Home Points
ξ Take your warfarin exactly as prescribed.
ξ Never double up on a dose if missed.
ξ Tell all of your health care team that you are taking a blood thinner.
ξ Know the signs and symptoms of bleeding and report them right away.
ξ Know the signs and symptoms of a blood clot and stroke and seek attention
ξ Tell your warfarin manager if there are any changes in your medicines, diet,
or activity level.
ξ Tell your warfarin manager if you were told to hold or stop warfarin before a
ξ Keep all scheduled visits or call promptly to reschedule.
Seek Emergency Care if you:
ξ Fall and hit your head
ξ Cough up or vomit blood (bright red or resembling coffee grounds)
ξ See blood in your urine or stool (enough to color toilet water)
ξ Severe headache or stomachache (worst in your life)
ξ Have an INR >9.9
ξ Chest pain or feeling short of breath
ξ Weakness on one side of body or slurred speech
Patient Dosing Sheet for Warfarin
Warfarin Indication _____________________________ Goal INR __________
Start date __________ Stop Date ___________ Tablet Strength __________ mg
Fill in INR from each lab draw date. Add dose in mg for each day of the week.
Make any changes to sheet as needed. Example provided
INR Su Mo Tu We Th Fr Sa
1/1 2.0 5 mg 3 mg 5 mg 3 mg 5 mg 3 mg 5 mg
Tell your warfarin manager of
Change in diet
Change in medicines
Missed or extra doses
Unusual bruising or bleeding
Upcoming procedures or trips
What is warfarin?
Warfarin sodium (Coumadin®, Jantoven®) is a drug that is often referred to as a
“blood thinner.” It works to prevent the production of clotting factors. This causes
the blood to take longer to form a clot and can also prevent a clot from getting
Why do I need a blood thinner?
It may be used to prevent a clot from forming or it can be used to treat an existing
clot. Some risk factors for developing blood clots are listed below.
Heart Valve Replacement
Treatment or prevention of DVT (deep vein thrombosis)
Treatment or prevention of PE (pulmonary embolism)
What dose should I take?
There is no standard dose. The amount needed varies for each person. The dose is
changed based on a blood test called the INR. It is a test to measure how long it
takes for your blood to clot.
The dose on your prescription bottle may not be the correct dose if it has changed.
If you do not know the dose you are supposed to take, then call your clinic.
How can I tell what dose I am taking?
Both generic (warfarin) and brand (Coumadin®, Jantoven®) will use the same color
theme, but tablets may be different shapes and sizes.
Dose Color Dose Color
1 mg Pink 5 mg Peach
2 mg Purple 6 mg Dark Green
2.5 mg Light Green 7.5 mg Yellow
3 mg Brown 10 mg White
4 mg Blue
What is my target INR range?
Your target INR range depends on why you are taking warfarin. Most people on
blood thinners will have a target INR range of 2-3 or 2.5-3.5. Your doctor will tell
you your INR range.
How often will my INR be checked?
You will need to be tested 2-3 times per week when you first start. Once your INR
and dose become more constant you may be able to test less often, about once per
month. Your warfarin manager will tell you how often to have your blood tested.
When should I take my warfarin?
Warfarin should be taken once a day. Take your dose exactly as prescribed and at
the same time every day. Most people are told to take their dose in the evening.
What happens if I miss a dose?
If you miss a dose and remember within 12 hours, you may take your dose. If it
has been more than 12 hours do not take your missed dose. Take your scheduled
dose for the current day and call your clinic. Be sure to report the missed dose to
your warfarin manager.
Never double up on your dose to make up for a missed dose. Never change your
dose unless your warfarin manager has told you to do so.
What does a warfarin manager do?
The person who manages your warfarin will determine your warfarin dose. To
find the dose that is right for you, they will ask you questions about your other
medications and lifestyle choices that can change your INR. Based on your
answers to these questions and the INR level, they will tell you what warfarin dose
to take and when to have the INR checked again.
Keep reading to see how medications, lifestyle and diet can change your INR.
Bleeding is the most common side effect. Minor bleeding can occur even if your
INR is within your target range.
Bleeding gums during tooth brushing
Bruising more than usual
Occasional nose bleeds
Prolonged menstrual bleeding (heavier than normal)
Prolonged bleeding after minor cuts
You may notice these side effects at times. If you have any question about
whether your bleeding is a concern call your warfarin manager.
Any bleeding that lasts for more than 10 minutes
Coughing up blood
Frequent nose bleeds, bleeding gums, or unusual bleeding
Red or dark brown urine
Red, black, or tarry stool
If you have a serious fall, hit your head or if you are having any of these major
bleeding side effects call your doctor or go to the Emergency Department
Interactions with other medicines
Prescription drugs, over-the-counter (OTC) products, herbal products and
supplements can affect how your blood thinner works. Any time you start or
stop a new medicine, herb, or vitamin you must tell your warfarin manager.
Listed below are some of the medicines that can increase your INR, decrease your
INR or put you at an increased risk for bleeding. These are not complete lists.
Medicines and other products that can increase your INR:
Alcohol (acute ingestion)
If you start any antibiotic you should call your warfarin manager
Medicines and other products that can decrease your INR:
Nutritional Drinks (some)
St. John’s Wort
Medicines and other products that can increase your risk of bleeding:
Fish Oil (omega-3 fatty acid)
To help prevent interactions, you must let your doctors and pharmacists know you
are taking warfarin. Also try to fill all your drugs at the same pharmacy. Your
pharmacist can help screen for interactions.
What lifestyle changes could affect my INR?
A change in activity level can affect your INR. Tell your warfarin manager if
you either increase or decrease your activity level. You should also avoid
activities that may place you at risk for injury, such as contact sports. Do not
play contact sports without talking to your doctor first. You may engage in low
risk physical activities, such as walking, jogging, or swimming.
If you are planning to travel tell your warfarin manager before your trip. You
may need to make plans for INR checks. You should also carry your medicines
with you at all times. Luggage may get lost and drugs left in cars may degrade
in extreme heat or cold.
Acute illness can change your response to warfarin. Tell your doctor or clinic if
you have any of the symptoms listed below.
Nausea or vomiting
Severe flu-like symptoms
If you have stopped eating or if your intake of food has changed due to
Started on an antibiotic
Limit alcohol to no more than 1 drink per day, or no more than 1 to 2 drinks on
a special occasion. Drinking more can greatly increase your risk for bleeding.
You should tell your warfarin manager about any amount of alcohol you
Surgical, Dental, or other Medical procedures
Tell all members of your health care team (surgeons, dentist, etc.) that you are
taking a blood thinner. You may need to stop taking it before certain
procedures. Be sure to tell your warfarin manager if you were told to stop or
hold your warfarin. They may need to change you to another type of blood
thinner before your procedure. See page 13 for more information.
If you are placed on a type of blood thinner that you inject, often called
“bridging,” keep taking this until your warfarin manager tells you to stop.
If you think you are or may become pregnant, tell your doctor right away.
Taking blood thinners while you are pregnant may cause harm to your unborn
baby. You should use a form of birth control. If you become pregnant your
doctor will instruct you about other treatment options.
Medical Alert Information
In case of an emergency or accident you will want to wear a medical alert
bracelet or necklace or carry an identification card. This will alert the health
care team that you are taking a blood thinner. Ask your local pharmacy or
doctor how you can obtain these.
How Diet Affects Warfarin
Some foods and other items you take can change the way your warfarin works
Foods that contain Vitamin K (see table)
Some nutritional drinks or tube feedings
Change in the amount of food you eat
Vitamin K is common to many foods, such as green leafy vegetables. They can
reduce the effects of warfarin when eaten in large amounts. You can still eat
Vitamin K type foods but you should eat the same amount of these foods from
week to week. Be aware of how many times per week and how many servings
you eat of food high in vitamin K.
Foods high in Vitamin K (serving size ½ cup cooked or 1 cup raw)
If these foods are a part of your diet, continue eating the same amounts
Green Tea Endive lettuce
Swiss chard Romaine lettuce
Brussels sprouts Green leaf lettuce
Parsley (okay as a garnish) Soy Beans/Edamame
Turnip and Mustard Greens
Other vegetables, fruits, cereals, dairy products, eggs, and meat contain smaller
amounts. See page 12 for more information.
ξ Eat the same amounts of Vitamin K foods from week to week.
ξ Note: usual serving size ½ cup cooked or 1 cup raw
Nutritional Drinks, Meal Replacement Shakes, and Weight Loss Shakes:
Meal replacement, weight loss, nutritional drinks or shakes may have high amounts
of vitamin K per serving. If you start one of these products tell your warfarin
manager. The following drinks have vitamin K. This is not a complete list.
ξ Boost® ξ Glucerna®
ξ Carnation Breakfast Essentials® ξ Slim Fast®
If your intake of food has decreased due to illness or if you plan on changing your
diet either short or long term let your warfarin manager know. They may need to
watch your INR more closely.
Signs and Symptoms of Blood Clots or Stroke
Warfarin is commonly used to prevent or treat blood clots or to prevent the
occurrence of a stroke. Below are common signs and symptoms of each.
Deep Vein Thrombosis (DVT) – blood clot commonly in the leg
Pain or tenderness in limb
Swelling or redness in limb
Skin warm to touch
Pulmonary Embolism (PE) – blood clot in the lung
Feeling short of breath
Cough (with or without blood)
Fast heart rate
Low grade fever or mild sweating
If you are having any of these above signs or symptoms of a blood clot this could
be a medical emergency and you should report to the nearest emergency
Stroke – sudden onset of the following:
Headache (described as the worst headache you ever had)
Changes in vision
Feeling weak on one side of the body
Slurred speech or difficulty speaking words
If you are having any of these above signs or symptoms of stroke this is a medical
emergency and you should call 911 immediately.
Vitamin K Content in Food
M = Medium H = High
For more information www.ptinr.com – vitamin K registry
Vitamin K content
Fats and Dressings
Margarine 1 Tbsp M (10)
Mayonnaise 1 Tbsp M (5)
Soybean, canola, and salad oils 1 Tbsp M (20)
Olive oil 1 Tbsp M (10)
Blueberries 1 cup M (25)
Grapes 1 cup M (20)
Asparagus 5 spears M (40)
Avocado 1 small M (30)
Broccoli 1 cup H (220)
Brussels sprouts 5 sprouts H (200)
Cabbage 1 cup M (40)
Cabbage, red 1 cup M (30)
Collard greens 1 cup H (840)
Endive (raw) 1 cup H (115)
Green Beans 1 cup M (15)
Green scallion (raw) 1 cup H (200)
Kale leaf (raw) 1 cup H (550)
Lettuce, bib, red leaf, romaine (raw) 1 cup H (65)
Lettuce, iceberg (raw) 2 cups M (30)
Mustard greens (raw) 1 cup H (280)
Parsley 1/4 cup H (245)
Peas, green (cooked) 2/3 cup M (40)
Soybeans 1 cup H (90)
Swiss chard 1 cup H (300)
Spinach leaf (raw) 1cup H (145)
Spinach (cooked) 1 cup H (900)
Turnip greens (raw) 1 cup H (140)
Watercress (raw) 1 cup H (85)
Dill pickle 1 cup M (25)
Cashews 1 cup M (45)
Stopping Warfarin Therapy for Procedures or Surgery
You are on a blood thinning medicine called warfarin. There may be a time when
you need to stop taking this drug if you will be having work done which might lead
to bleeding. This may include: a dental visit, biopsy, minor or major surgery.
Ask the doctor or dentist if you will need to stop this blood thinner and for how
long it should be stopped. If they want you to stop taking your warfarin, please
tell them to contact the clinic that manages your warfarin. You should also
call the clinic that manages your warfarin to tell them you will need to stop it for a
Before stopping warfarin for a procedure or surgery your doctor will consider the
ξ Reason for warfarin
ξ Your individual risk for clotting or stroke
ξ The clotting and bleeding risk of the procedure
ξ How long you will need to off of the warfarin
Please know there are some procedures where warfarin may be continued since
bleeding risk is considered low:
ξ Simple dental procedures – including extractions
ξ Cataract surgery
ξ Diagnostic or screening colonoscopies
ξ Minor skin surgeries
If you need to stop warfarin your doctor may start you on an alternative
anticoagulant that you inject into the skin. Follow the directions closely on when
to give this new medication and when stop and restart your warfarin. There may
be some time when you are taking both the warfarin and injection until your INR
returns into goal range.
Select the best answer for each question.
1. What is the name of the blood test used to monitor warfarin levels?
b. Platelet count
c. Red blood cell count
2. How often do you need a blood test?
a. Once a year
b. At regular intervals, decided on by my doctor or clinic
c. Only after a dose changes
3. If your INR is high, you may be at risk for:
b. Serious bleeding
c. Heart attack
4. What should you do if you miss a dose of warfarin?
a. Take my dose as soon as I remember on the same day. If it is the next
day, I will just resume my normal dosing and tell my healthcare provider.
b. Nothing- it is okay to skip one dose
c. Take an extra pill to "catch up"
5. What should you do if you want to take an over-the-counter medicine or
a. I can't take any over-the-counter medicines or vitamins while on warfarin
b. Go ahead and start the new medicines, your provider does not need to
c. Call my provider and ask if the new item will be safe with warfarin.
6. What should you do if you really enjoy eating spinach or other green, leafy
a. Stop eating them altogether
b. Only eat them if INR is high
c. Be constant with the amount that I eat
d. Just eat 1 big bowl per month
7. Who should you tell that you take warfarin?
a. All my doctors
b. My dentist
c. My pharmacist
d. All of the above
1. Ageno W, Gallus AS, Wittkowsky A, et al. Oral Anticoagulant Therapy: Antithrombotic
Therapy and Prevention of Thrombosis, 9th ed. American College of Chest Physicians
Evidence Based Clinical Practice Guidelines. CHEST. 2012;141:e44s-88s.
2. Holbrook A, Schulman S, Witt D, et al. Evidence Based Management of Anticoagulant
Therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed. American
College of Chest Physicians Evidence Based Clinical Practice Guidelines. CHEST.
3. Holbrook AM, et al. Systematic overview of warfarin and its drug and food interactions.
Arch Intern Med. 2005; 165:1095-1106.
4. Wittkowsky AK. Drug interactions update: drug, herbs and oral anticoagulation. J
Thromb Thrombolysis. 2001; 12:67-71.
5. Warfarin [package insert]. Princeton, NJ: Bristol-Meyers Squibb Pharma Company;
revised Jan 2009.
Warfarin Emergency Pocket Card
Keep this card in your wallet or purse in case of emergencies. It allows emergency
personnel to know that you are on warfarin.
I am using Warfarin, an anticoagulant.
Please tell this immediately to anyone providing medical care to me.
Birth date: Weight: Blood Type:
On warfarin for:
In an emergency, please notify:
Phone: ( )
Doctor’s Phone: ( )
Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor. This
is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because each
person’s health needs are different, you should talk with your doctor or others on your health care team when using
this information. If you have an emergency, please call 911. Copyright 12/2014. University of Wisconsin Hospitals
and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#6900.