Warfarin (Coumadin®)

Other Names: Coumadin®

What is Warfarin Used For?

Warfarin decreases the amount of blood clotting factors the body produces, making the blood less likely to form abnormal clots. Commonly known as a "blood thinner" (although it does not actually thin the blood), Warfarin will not dissolve clots that have already formed, but will stop them from getting any larger. It also reduces the risk of blood clots breaking off and traveling to vital organs.

How Do You Take Warfarin?

Always take your Warfarin at the same time each day. Dosage is determined by a regular blood test called an "INR" test. Testing will be more frequent at the beginning of your therapy and usually less frequent once the dosage is stabilized.

What Special Instructions Do You Need To Know?

• Try not to miss any doses. If you miss a dose, take it as soon as you remember unless it is almost time for your next dose. In that case, skip the missed dose and take the next dose at the usual time. Do not double the dose.
• Notify your doctor if you have missed a dose as it may affect your blood test.
• Do not stop taking this medication without first consulting your doctor.

Are There Side Effects From Taking Warfarin?

• Many medications affect the action of Warfarin. Check with the pharmacist regarding all drugs that you take to be sure you can take them safely. This includes any over-the-counter remedies, herbal or vitamin supplements that you can buy without a prescription.
• Do not make major changes to your diet. Vitamin K, found in many foods, helps your blood make clots. It is important to keep the level of vitamin K in your diet consistent as sudden changes can affect the clotting time (INR).

When Should You Call Your Doctor?

Call your healthcare provider (doctor, nurse or pharmacist) if you have any questions or concerns or if you experience any side effects you think may be related to the use of Warfarin, such as:

• Nausea, vomiting, diarrhea, cramps, headaches, dizziness
• Unusual heavy bleeding from a cut/wound
• Bleeding from the gums or blood in the urine/stool
• Vomiting blood or a substance resembling coffee grounds

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This information is designed for use in conjunction with teaching by a qualified health professional.
Prepared by: Cardiology Pharmacist's Group

Disclaimer
Reviewed by Alberta clinical experts. Brought to you by HealthLink Alberta. Copyright.
This material is designed for information purposes only. It should not be used in place of medical advice, instruction and/or treatment. For more health advice call Capital Health Link at 780-408-LINK (5465) 24 hours a day, seven days a week. In Alberta, call Toll-free: 1-866-408-LINK (5465)