Your doctor has prescribed a medicine to prevent blood clots. The generic name for this medicine is warfarin. Coumadin® (COO-ma-din) is the name of the first brand of warfarin that was available. In this sheet, the name “Coumadin®” will be used because that is the name that many patients are most likely to hear. Warfarin and Coumadin® are the same medicine. All of this information applies to warfarin and to Coumadin®.
Coumadin® is an anticoagulant (an-tih-ko-AG-you-lent). Coumadin® is also referred to as a blood thinner. While it does not actually thin your blood, it will prevent blood clots from forming in the blood vessels. If you already have a blood clot, Coumadin® helps to keep the blood clot from getting larger and will protect you from forming new clots.
Your doctor may also prescribe Coumadin® even if you don’t currently have a blood clot. This is to protect you from developing blood clots if you have certain medical conditions.
It is very important to follow the instructions for your anticoagulant. Coumadin® is a medication that you take by mouth once a day. You should try to take your Coumadin® at the same time every day, preferably in the evening.
Your doctor will prescribe the dose of Coumadin® that is best for you. Coumadin® tablets are made in several strengths. Each tablet strength comes in a different color. This is called “color coding.” Several companies make generic warfarin tablets, but some use different color codes and often different shapes.
Do not rely on the color of your tablet to check the dose strength. Always check the dosage numbers on the tablet or the strength listed on the bottle. If your medicine looks different from what you had before or you are in doubt about the strength of your Coumadin® tablets, ask your pharmacist.
While you take Coumadin®, your doctor will order a blood test called PT/INR to see how long it takes your blood to clot. “PT” stands for protime. “INR” stands for international normalized ratio. The test results show if your dose needs to be adjusted. If your dose must be changed, your doctor or health care provider will call you and tell you the new dose to take.
It is very important that you keep all your appointments for blood tests and follow-up visits with your doctor. Your doctor will decide how long you need to take your anticoagulant.
If you miss a dose of Coumadin®, take the missed dose as soon as possible on the same day. Do not take a double dose the next day to make up for a missed dose. Call your health care provider any time you have missed a dose.
You will be able to do most of your normal activities while taking this medicine. You need to follow some precautions.
If you have any of the following, call your doctor or anticoagulation provider:
Vitamin K from food and dietary supplements can interfere with the blood-thinning effects of Coumadin®. It is important to keep your intake of Vitamin K the same every day. Changing the amount of Vitamin K you get could result in bleeding or an unwanted blood clot.
It is very important to be consistent. For instance, if you eat a half-cup of a high Vitamin K food daily, continue to eat this same amount each day.
High Vitamin K foods (listed with the highest first)
For example, it would not be wise to eat leaf lettuce at every meal and then stop eating it entirely. It would be better to substitute another medium Vitamin K food from the list below for the leaf lettuce.
Medium Vitamin K foods (listed with the highest first)