New kid on the block

For more than 60 years, Coumadin, (generically known as Warfarin), has been the only “blood thinner” available for millions of people with a common irregular heart rhythm known as atrial fibrillation. A newly approved alternative to Coumadin (Warfarin) known as Pradaxa, fights stroke better than Coumadin for patients with atrial fibrillation, with less bleeding into the brain, less interactions and without the need for blood tests.
Atrial fibrillation is an irregular heart rhythm that is associated with an increased risk of developing a harmful, or possibly fatal stroke, due to the formation of a blood clot. To reduce the likelihood of blood clots being formed, patients with atrial fibrillation must take specific types of blood thinners. Up until recently, the best available drug was Coumadin (Warfarin). Warfarin is a very good drug, and remains a mainstay for many patients with a history of mechanical heart valves, irregular heart rhythms and blood clots in the legs, lungs, etc. Coumadin effectively prevents the formation of clots in the bloodstream. It is widely available, and inexpensive. However, anyone who has either taken Coumadin or managed patients taking Coumadin, knows it can be difficult to regulate. Blood tests must be done regularly to determine the proper dosing regimen. A standardized blood test, called an INR, is used to evaluate the effectiveness of Coumadin. Regulating Coumadin levels is a delicate balance between too much and too little. If the INR is too low, you’re not receiving enough of the drug, increasing your risk of forming blood clots. If the INR is too high, your blood is too thin, making you prone to bleeding. In addition, there are multiple factors that can affect Coumadin – what you eat and drink, your health, and a number of drugs, vitamins, supplements, and herbal remedies.
Several alternatives to warfarin have been developed over the last few decades. Some had fewer side effects than warfarin, but weren’t as effective. Others worked as well as warfarin, or better, but were harmful to the liver.
Pradaxa beats warfarin in both effectiveness and safety: in clinical trials, it decreased the risk of stroke or death more than warfarin with fewer episodes of major bleeding.
Here are answers to some common questions about Pradaxa:
How does it work?
Pradaxa prevents blood clots from forming by blocking the action of thrombin, a protein that circulates in the bloodstream. One of thrombin’s key jobs is to convert another soluble protein, called fibrinogen, into strands of fibrin. These strands stick to the blood vessel wall, forming a net-like complex. A blood clot forms as red blood cells become entangled in the fibrin web.
Who is it for?
The FDA approved Pradaxa to reduce the risk of stroke and other problems caused by blood clots in people with nonvalvular atrial fibrillation. Trials have not yet determined if Pradaxa can replace warfarin for people with other conditions, such as deep-vein thrombosis or a mechanical heart valve. Only your Dr. or healthcare provider can advise you as to whether or not you are a candidate for taking Pradaxa.
What are its advantages?
Pradaxa isn’t affected by diet, as is the case with warfarin, so you can eat green, leafy vegetables and other foods rich in vitamin K without worrying about it effecting the drug. The dose of Pradaxa needn’t be calculated for your weight; it is more a one-size-fits-all medication, like aspirin. Finally, you don’t need routine blood tests to measure your international normalized ratio (INR), as are needed with warfarin.
What are its disadvantages?
The main drawback is the upfront cost. A year’s supply of warfarin, which is available as a generic medication, costs about $360. Pradaxa will cost nearly $2,500 a year. But this could be offset by the cost (not to mention the time spent traveling to the doctor’s office) of not having to do repeated INR tests.
How do I take Pradaxa?
Take one capsule in the morning with breakfast, and another about 12 hours later with your evening meal. Do not break open the capsules or chew them.
What if I miss a dose?
If you forget to take Pradaxa at breakfast, but remember a couple of hours later, go ahead and take it. If you remember later, and are supposed to take the next dose within six hours, wait until then and take only the evening dose. Do not take a double dose. If you forget to take your evening dose, take only a single dose at breakfast.
What are the common side effects?
Because Pradaxa inhibits clotting, bleeding is the main side effect. This runs from easy bruising, or shaving cuts that seem to take forever to stop bleeding, to more serious bleeding into the stomach or brain. The drug also causes marked stomach upset in about two in 100 people who take it.
Thoughtful switch
At first glance, it looks like everyone with nonvalvular atrial fibrillation should swap their Warfarin for Pradaxa. But it’s worth taking a longer, harder look. The main clinical trial included 18,000 people who took Pradaxa for two years. We will undoubtedly learn more about the drug — its effectiveness, side effects, safety, and interactions with other drugs — after it has been used by hundreds of thousands of people, and for longer periods. For some people, switching right away to Pradaxa makes sense. For others, it is worth adopting a watch-and-wait strategy.
Talk with your doctor to see which approach is right for you.
Lisa M Ennis FNP

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