Q: I've been seeing commercials for new anticoagulants that might replace my Coumadin. What should I know about them?
A: Good question. For the last 40-plus years, people who have had a heart attack, atrial fibrillation, risk of stroke or who have had a deep vein thrombosis (blood clot in legs or elsewhere) or a pulmonary embolism (blood clot in lungs), have been given a prescription for Coumadin, the name brand of warfarin, an oral medicine to reduce blood clotting in the body.
It's often referred to as a blood thinner even though it doesn't thin blood. It is also sometimes called rat poison as it was used for that before it was used (in very low doses) in people.
Warfarin is not the easiest drug to use, as it can cause bruises, nose bleeds or other bleeding episodes. Eating foods like lettuce and spinach require modifying your dose. And probably the most time-consuming and costly consequence of taking warfarin is that very frequent blood samples must be taken and tested to measure the time it takes for your blood to clot.
So patients using this medicine were excited to learn that at least four new agents to reduce blood clotting -- without the need for frequent blood testing -- were introduced in the U.S. They are Xarelto (rivaroxaban), Pradaxa (dabigatran), Eliquis (apixaban) and Savaysa (edoxaban). It's easier to determine the right dosage of these medicines, and there aren't dietary interactions as with warfarin.
Here's the catch: warfarin can be counteracted if you are wounded in an accident or need emergency surgery. This older drug works by decreasing the amount of vitamin K produced by the body, and so simply administering more of the vitamin will reverse warfarin's effects. Another strategy is to give large quantities of platelets or whole blood, or to administer infusions containing the needed clotting factors.
But there aren't compounds available that will quickly counteract the effects of most of the newer anticoagulants, except for Pradaxa. It is not sufficient to stop taking the drug because its action continues and you can't wait a few days for some surgical procedures. So using them involves something of a gamble.
So, what do you do if you're on warfarin and are interested in trying a newer drug?