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Oral Anticoagulants
Oral anticoagulants work to prevent blood clots from forming. Patients who have atrial fibrilation may need to take an oral anticoagulant, like warfarin, to prevent a stroke. When taking warfarin, it is important to note that your doctor will require very careful monitoring of the medication, and it may be necessary to change your dose periodically. Your doctor or pharmacist will use a blood test that measures your International Normalized Ratio (INR) to adjust your dose. It is important to take the medication exactly as directed by your doctor or pharmacist to ensure that you are not at risk to develop another stroke or a bleed.
INR Testing
Patients who take warfarin should have their International Normalized Ratio (INR) monitored frequently throughout the duration of their therapy. An INR indirectly indicates the amount of time it takes for your blood to clot. In addition, the INR should target a specific INR value that is optimal for prevention of stroke.
- For prevention of stroke, an INR value in the range of 2-3 with a goal of 2.5 is desired.
It is extremely important to have your INR regularly monitored for the following reasons. Too much warfarin could potentially increase your INR and as a result, put you at risk for excess bleeding. On the other hand, too little warfarin could potentially decrease your INR and put you at risk for developing a clot and another stroke.
Make sure you have your INR initially monitored twice in the first week you begin treatment. Then once your INR has stabilized, have your INR monitored every 4-6 weeks or more often if the INR is not within goal range.
Dietary Considerations
It is important to eat a normal , well-balanced diet everyday. Because the amount of vitamin K in your body affects the way warfarin works, unusual inconsistent consumption of foods with a high amount of vitamin K may affect the safety and effectiveness of warfarin. Foods with a high amount of vitamin K include liver, broccoli, spinach, cauliflower, cabbage, brussel sprouts, kale, and other dark green leafy vegetables. Because of this fact, strictly vegetarian diets that consist of high amounts of vitamin K containing foods should be avoided. If you use any dietary supplements or vitamin products, check with your doctor or pharmacist to make sure they do not contain high amounts of vitamin K.
Avoid drinking alcohol while taking this drug because it may increase the risk of stomach bleeding.
What to Watch For
Because warfarin can cause bleeding, notify your physician as soon as possible if you experience any of the following:
- Excessive nose bleeds
- Excessive bleeding from cuts or scrapes
- Excessive bleeding from your gums
- Discoloration of your stools (dark and tarry) or bright red blood in stools
- Heavy menstrual bleeding
- Unusual or easy bruising
- Persistent nausea or vomiting
- Stomach pain
- Yellowing of eyes/skin
- Persistent, severe back pain
Although unlikely, immediately notify your physician if you experience a severe allergic reaction to warfarin. Symptoms of an allergic reaction include rash, itching, swelling, severe dizziness, and trouble breathing.
Drug Interactions
Due to the fact that warfarin interacts with many commonly used medications and medication ingredients, it is important that you inform your physician or pharmacist about any new prescription and non-prescription medications, supplements, vitamins, and herbals that you may be taking. Some common interacting drugs include:
- acetaminophen
- agents that dissolve blood clots
- agents that lower cholesterol
- alcohol
- allopurinol
- amiodarone
- antibiotics or medicines for treating bacterial, fungal or viral infections
- antiinflammatory drugs, NSAIDs, such as ibuprofen
- aprepitant
- aspirin
- azathioprine
- barbiturate medicines for inducing sleep or treating seizures
- bosentan
- cimetidine
- cyclosporine
- disulfiram
- female hormones, including contraceptive or birth control pills
- fish oil (omega-3 fatty acids) supplements
- herbal products such as danshen, garlic, ginkgo, ginseng, green tea, or kava kava
- influenza virus vaccine
- male hormones
- medicines for some types of cancer
- certain medicines for heart rhythm problems
- certain medicines for high blood pressure
- quinidine, quinine
- seizure or epilepsy medicine such as carbamazepine, phenytoin, and valproic acid
- testolactone
- thyroid medicine
- tolterodine
- vitamin K (including vitamin, mineral, and food supplements that contain vitamin K)
You can also check if a medication, supplement or food you are currently taking interacts with warfarin by using our drug interaction checker.
Importance of Compliance
It is extremely important that you take warfarin exactly as prescribed by your physician. Any unmonitored changes in your warfarin treatment could result in serious bleeding or clotting complications.
It is best to take warfarin around the same time everyday. If you miss a dose of warfarin at the scheduled time, take the dose as soon as you remember if it?s the same day. If you miss a dose and do not remember until the next day, do not double the dose to make up for the missed dose. Be sure to report any missed doses or mistakes in taking doses to your healthcare provider.
Finally, be sure to not run out of warfarin tablets. Get your prescription refilled on time and alert your doctor if you need additional refills on your warfarin prescription
Drugs in the class
Warfarin Tablets (Coumadin Tablets, Jantoven Tablets) |
