Disclaimer
References in this document to Coumadin®, the brand name used by Bristol-Myers Squibb to market its product, warfarin, are made solely for the ease of patient identification. This reference does not constitute an expressed or implied endorsement of this brand by the Cleveland Clinic. Other equivalent brands of anticoagulant medications may be available and appropriate for patient use.
* Throughout this document, the anticoagulant medication will be referred to by the commonly used generic name of warfarin.
Introduction
The better you understand your medication, the more successful your anticoagulation therapy will be and the less likely you are to have complications from the medication.
If you have any questions about your medication, please discuss them with your health care provider (doctor, pharmacist, or nurse).
What warfarin does and how it works?
Your doctor has prescribed an anticoagulant medication. "Anti" means against and "coagulant" means causing blood clotting. Warfarin is a type of anticoagulant medication that helps prevent clots from forming in the blood.
You have been prescribed warfarin because your body may be making blood clots or you may have a medical condition known to promote unwanted blood clots. Blood clots can move to other parts of your body and cause serious medical problems. Warfarin will not dissolve a blood clot. However, over time the blood clot may dissolve on its own. Warfarin may also prevent other clots from forming.
Blood testing
In order for your health care provider to determine the correct dose of warfarin, it will be necessary for you to have blood tests. The tests are performed in a laboratory or anticoagulation clinic, usually once a week to once a month, as directed by your doctor.
The prothrombin time (PT or protime) test is used to calculate your International Normalized Ratio (INR). Your INR will help your health care provider determine how fast your blood is clotting and whether your medication dose needs to be changed.
Note: Because your dosage might change from time to time, it might be helpful to use "Your Personal Dosage Calendar" at the end of this handout.
Illness, diet, medication changes, and physical activities may affect your INR. Tell your health care provider about changes in your health, medications (prescription and over-the-counter) or lifestyle so appropriate dosage adjustments can be made.
Tablet appearance
Coumadin brand tablets are round and scored, which means they can be broken in half. Each tablet color represents a different strength. The strength of the tablet is measured in milligrams (mg) as follows:
- 1 mg - pink
- 2 mg - lavender
- 2.5 mg - green
- 3 mg - tan
- 4 mg - blue
- 5 mg - peach
- 6 mg - teal or blue-green
- 7.5 mg - yellow
- 10 mg - white