Examples

Coumarins

Low-molecular-weight heparins (LMWH)

Direct thrombin inhibitor (only used in the hospital)

Unfractionated heparins (UH)

How It Works

Anticoagulant medicines (also known as blood thinners) help prevent the formation of blood clots by increasing the time it takes a blood clot to form. This prevents a clot that has already formed from getting larger and reduces the chances that pieces of a clot will break off and cause a heart attack or stroke.

Why It Is Used

Anticoagulants are used after heart valve replacement surgery. After surgery, you have a higher risk for dangerous blood clots.

• If you have a mechanical valve (made with metal or plastic), you will take anticoagulants for the rest of your life.
• If you have a biological valve (made with tissue), you will take anticoagulants for a few months after surgery.

After heart valve replacement surgery, both warfarin and one of several types of anticoagulant medicines—a low-molecular-weight heparin, an unfractionated heparin, or another antithrombotic medicine—are started. Coumadin is given in pill form while the other medicines are given as a shot. The injected medicines act immediately, while Coumadin takes several days to become effective. When warfarin begins to work, the other medicines are stopped.

How Well It Works

Anticoagulants lower the risk of dangerous blood clots after valve replacement surgery.¹

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

• Usually the benefits of the medicine are more important than any minor side effects.
• Side effects may go away after you take the medicine for a while.
• If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Bleeding: Call 911 or other emergency services right away if:

• You cough up blood.
• You vomit blood or what looks like coffee grounds.
• You pass maroon or very bloody stools.
• You have a sudden, severe headache that is different from past headaches. (It may be a sign of bleeding in the brain.)