[Posted 08/16/2007] FDA approved updated labeling to include pharmacogenomics information to the CLINICAL PHARMACOLOGY, PRECAUTIONS, and DOSAGE AND ADMINISTRATION sections of the prescribing information for the widely used blood-thinning drug, warfarin (Coumadin). This new information explains that people’s genetic makeup may influence how they respond to the drug. Specifically, people with variations in two genes may need lower warfarin doses than people without these genetic variations. The two genes are called CYP2C9 and VKORC1. The CYP2C9 gene is involved in the breakdown (metabolism) of warfarin and the VKORC1 gene helps regulate the ability of warfarin to prevent blood from clotting.
The dosage and administration of warfarin must be individualized for each patient according to the particular patient’s prothrombin time (PT) / International Normalized Ratio (INR) response to the drug. The specific dose recommendations are described in the warfarin product labeling, along with the new information regarding the impact of genetic information upon the initial dose and the response to warfarin. Ongoing warfarin therapy should be guided by continued INR monitoring. For more information visit the FDA website at: [Web].
[Posted 10/06/2006] FDA and Bristol-Myers Squibb notified pharmacists and physicians of revisions to the labeling for warfarin (Coumadin), to include a new patient Medication Guide as well as a reorganization and highlighting of the current safety information to better inform providers and patients.
The FDA regulation 21CFR 208 requires a Medication Guide to be provided with each prescription that is dispensed for products that FDA determines pose a serious and significant public health concern. Information about all currently approved Medication Guides is available at: [Web]. For more information visit the FDA website at: [Web], and [Web].
What is this medicine?
WARFARIN (WAR far in) is an anticoagulant. It is used to treat or prevent clots in the veins, arteries, lungs, or heart.
This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:
Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. You can take this medicine with or without food. Take your medicine at the same time each day. Do not take it more often than directed. Do not stop taking except on the advice of your doctor or health care professional.
A special MedGuide will be given to you by the pharmacist with each prescription and refill. Be sure to read this information carefully each time.
Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What if I miss a dose?
It is important not to miss a dose. If you miss a dose, call your healthcare provider. Take the dose as soon as possible on the same day. If it is almost time for your next dose, take only that dose. Do not take double or extra doses to make up for a missed dose.
What may interact with this medicine?
Do not take this medicine with any of the following medications:
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medicine?
Visit your doctor or health care professional for regular checks on your progress. You will need to have your blood checked regularly to make sure you are getting the right dose of this medicine. When you first start taking this medicine, these tests are done often. Once the correct dose is determined and you take your medicine properly, these tests can be done less often.
While you are taking this medicine, carry an identification card with your name, the name and dose of medicine(s) being used, and the name and phone number of your doctor or health care professional or person to contact in an emergency.
You should discuss your diet with your doctor or health care professional. Many foods contain high amounts of vitamin K, which can interfere with the effect of this medicine. Your doctor or health care professional may want you to limit your intake of foods that contain vitamin K. Foods that have moderate to high amounts of vitamin K include brussel sprouts, kale, green tea, asparagus, avocado, broccoli, cabbage, cauliflower, collard greens, liver, soybean oil, soybeans, certain beans, mustard greens, peas (black eyed peas, split peas, chick peas), turnip greens, parsley, green onions, spinach, and lettuce.
This medicine can cause birth defects or bleeding in an unborn child. Women of childbearing age should use effective birth control while taking this medicine. If a woman becomes pregnant while taking this medicine, she should discuss the potential risks and her options with her health care professional.
Avoid sports and activities that might cause injury while you are using this medicine. Severe falls or injuries can cause unseen bleeding. Be careful when using sharp tools or knives. Consider using an electric razor. Take special care brushing or flossing your teeth. Report any injuries, bruising, or red spots on the skin to your doctor or health care professional.
If you have an illness that causes vomiting, diarrhea, or fever for more than a few days, contact your doctor. Also check with your doctor if you are unable to eat for several days. These problems can change the effect of this medicine.
Even after you stop taking this medicine, it takes several days before your body recovers its normal ability to clot blood. Ask your doctor or health care professional how long you need to be careful. If you are going to have surgery or dental work, tell your doctor or health care professional that you have been taking this medicine.
What side effects may I notice from receiving this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
signs and symptoms of bleeding such as bloody or black, tarry stools, red or dark-brown urine, spitting up blood or brown material that looks like coffee grounds, red spots on the skin, unusual bruising or bleeding from the eye, gums, or nose
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medicine?
Keep out of the reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from light. Throw away any unused medicine after the expiration date.
NOTE:This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.
Remember, keep this and all other medicines out of the reach of children,
never share your medicines with others, and use this medication only for the indication prescribed.
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