For people at risk of developing dangerous blood clots—a main cause of stroke and other serious conditions—warfarin (Coumadin) has long been the granddaddy of anticoagulant medication. This pill is taken by about 3 million Americans.
Now: The FDA has approved four newer oral anticoagulants. (Other anticoagulants such as enoxaparin and heparin are available only as injections.) While the newer oral anticoagulants may offer certain benefits over warfarin, they are not the best choice for everyone.
Why this matters: Using the wrong anticoagulant drug (or dose) can have dire consequences, such as life-threatening bleeding in the brain or gastrointestinal tract.
Anticoagulants are used by people who are at increased risk for ischemic (caused by a blood clot) stroke and transient ischemic attacks, or “ministrokes”…or deep vein thrombosis (a blood clot in a deep vein), which can lead to a deadly pulmonary embolism (a blood clot in the lung). Anticoagulants also help prevent clots from forming in people who have an abnormal heartbeat (atrial fibrillation)…or have received a heart-valve replacement.
Warfarin has been used in the US for decades and is very effective at protecting high-risk people from blood clots. It’s the only anticoagulant approved for use in people with mechanical heart valves.
Here’s the catch: The amount of warfarin in the body must be regularly measured via a blood test called the International Normalized Ratio (INR). This allows doctors to monitor and customize the dosage for each individual patient, but it also means that you’ll need frequent blood tests—weekly or monthly—to make sure that the drug is working properly. This testing is crucial, but not all patients do it as often as they should.
In addition, when you take warfarin, you must closely monitor your diet. Foods that contain vitamin K, such as leafy greens, broccoli and spinach, help your body make normal clotting proteins, which means they will work against the drug’s action. For this reason, you should be consistent in the amounts of vitamin K–rich foods that you eat. Otherwise, the drug’s effectiveness will be affected.
Also, warfarin interacts with more than 700 prescription and over-the-counter drugs as well as many supplements, including ginkgo biloba, St. John’s wort, coenzyme Q10 and others. You need to keep your doctor informed about everything you take. The newer drugs have far fewer interactions.
Four alternatives to warfarin are now available in the US—dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis) and edoxaban (Savaysa). Clinical trials show a lower risk for hemorrhagic (bleeding) stroke with the newer drugs compared with warfarin. There is also a reduction in overall strokes with some of the newer drugs.
Other differences include…
• No regular blood work. There is no good way to monitor levels of these new drugs in the body, but they have proved effective without monitoring levels, so you won’t have to endure weekly or monthly blood tests, as needed when using warfarin. However, the complete safety profile of new drugs is also unknown, and doctors cannot customize dosing for each individual.
• There are no foods that work against the newer drugs, as there are with warfarin. The newer drugs are as effective as warfarin no matter what you eat.
• No antidote. If a patient’s blood becomes too thin and bleeding becomes uncontrollable, there is nothing to reverse it when using three of the four newer anticoagulants. (Dabigatran has an antidote—idarucizumab (Praxbind)—and antidotes for the other three are in development). Warfarin does have an antidote.
Editor’s note: More than 100 lawsuits have been filed on behalf of patients who were injured or died due to a major bleeding event after taking Xarelto. The manufacturer of Pradaxa agreed to pay $650 million last year to settle about 4,000 similar claims.
• A link to kidney function. The newer drugs can be affected by your kidney function, so your doctor will need to consider this when choosing a medication and its dose.
If you’re taking warfarin and doing well, you don’t need to think about trying one of the newer drugs—unless there are strong, compelling reasons to do so (such as an inability to get necessary blood work). Remember, newer drugs don’t have as long a track record as older ones. That’s why it’s important to thoroughly discuss your medication options with your doctor.
What to consider…
• If you have difficulty remembering to take pills throughout the day, once-a-day Xarelto or Savaysa may be best for you.
• If you play sports or have a hobby that may cause a bleeding accident, warfarin might be best.
• If you have a history of stomach problems or gastrointestinal bleeding, you may want to avoid Pradaxa and Xarelto—both medications have the highest risk for these complications.
• If cost is an issue, you may want to consider warfarin. The newer anticoagulants are marketed only in brand-name versions that are much more expensive (even with insurance coverage) than warfarin, which is available in generic form. With warfarin, you also have the cost of the necessary routine blood work, but this expense may be covered by your insurance.
Caution: Do not stop using an anticoagulant without consulting your physician—this drug helps control your increased risk for stroke and other blood clot complications. Because of the bleeding risk associated with anticoagulants, people who use these drugs should wear a medical identification bracelet.
