If you get a blood clot in your leg or another large blood vessel called a deep vein thrombosis (DVT), your treatment will include medications known as blood thinners. These drugs, also called anticoagulants, make it harder for your blood to clot. That stops your existing blood clot from getting bigger while your body works to get rid of it, and helps keep you from getting another blood clot.
Anticoagulants come in different forms that work in different ways. One kind you may get after a DVT is called a direct thrombin inhibitor.
How Do Direct Thrombin Inhibitors Work?
There’s an enzyme in your blood called thrombin. When you’re bleeding, its job is to turn a particular protein into strong threads that trap platelets and help them clump together to plug the leak. That makes a blood clot or a scab. Direct thrombin inhibitors stop this process, so your blood flows more freely and clots are less likely to form.
Who Gets Direct Thrombin Inhibitors?
Direct thrombin inhibitors are used in the second (long-term) and third (extended) phases of anticoagulation treatment for a DVT.
Dabigatran. You may get a drug called dabigatran (Pradaxa) 5-10 days after you’re first treated with a different blood thinner by a shot or an IV directly into your vein. Dabigatran is a pill you take twice a day while your blood clot is allowed to resolve naturally, or is dissolved with other medications. It keeps the clot from getting bigger and helps prevent other clots from forming. It’s often prescribed for about 3 months, long enough for the clot to go away.
You may have health or lifestyle issues that make you more likely to get more blood clots. In that case, your doctor may have you take dabigatran longer – possibly the rest of your life – to prevent another clot.
You might also get dabigatran to prevent blood clots if you have an irregular heartbeat not caused by a heart valve problem, or after hip surgery.
Argatroban and bivalirudin. It’s rare, but some people have a dangerous reaction to the anti-clotting drug heparin. They might get one of two other direct thrombin inhibitors to treat a DVT, argatroban or bivalirudin (Angiomax). These are given through your vein. They’re also used to prevent blood clots during certain heart procedures.
How Well Do Direct Thrombin Inhibitors Work?
This is a relatively new kind of drug. It was tested (before getting approval) against the drug warfarin, which for decades has been the go-to blood thinner for DVT treatment. It worked just as well, and was slightly less likely to lead to uncontrolled bleeding.
Since then, researchers have compared studies on dabigatran to those on other newer blood thinners known as Xa inhibitors, including rivaroxaban (Xarelto) and apixaban (Eliquis). They found that they all work just about equally well, and are equally safe.
Grouped together, these newer blood thinners are called direct oral anticoagulants. Compared to warfarin, they:
- Start working faster
- Don’t require frequent blood testing to see how they’re working
- Don’t need the dose adjusted
- Have fewer interactions with food
- Leave your system faster
- Are more expensive
What Are the Risks of Direct Thrombin Inhibitors?
All blood thinners make you more likely to have uncontrolled bleeding. But it’s somewhat easier to stop with direct thrombin inhibitors, because they leave your system within a day or so once you stop taking them. And a medication called idarucizumab (Praxbind) can reverse the effects of dabigatran in an emergency to stop bleeding.
- You should stop taking dabigatran before surgery or a procedure that requires a spinal puncture or an epidural. Your doctor will tell you how many days ahead of time.
- Don’t stop taking it without talking to your doctor. And be careful not to miss a dose. That can make you more likely to get a blood clot.
- Don’t take it if you have an artificial heart valve.
- It can also cause an upset stomach.