Anticoagulants and Antiplatelets

What are anticoagulants and antiplatelets?

Anticoagulants and antiplatelets are medicines that help treat or prevent blood clots. The most commonly used anticoagulants are:

fondaparinux (Arixtra)
heparin and low molecular weight heparin (LMWH), such as Lovenox and Fragmin
thrombin inhibitors, such as argatroban, bivalirudin (Angiomax), and lepirudin (Refludan)
warfarin.

The most commonly used antiplatelets are:

abciximab (ReoPro)
aspirin
clopidogrel (Plavix)
eptifibatide (Integrilin)
ticlopidine (Ticlid)
tirofiban (Aggrastat).

How do they work?

When blood clots, it turns from a liquid into a solid. Although anticoagulants are often called blood thinners, they actually increase the time it takes a blood clot to form. Antiplatelet medicines decrease the chance a blood clot will form because they prevent certain blood cells, called platelets, from becoming sticky and clumping together.

Blood clotting keeps the body from losing too much blood from wounds. But sometimes blood clots can block blood flow and cause problems such as:

stroke when blood flow to the brain is blocked
heart attack when blood flow to the heart is blocked
deep vein thrombosis (DVT) when a blood clot forms in a vein in the legs and may travel to the lungs, causing a pulmonary embolism (PE) and blocking blood flow to the lungs.

When are they used?

Anticoagulants and antiplatelets are used to treat or prevent conditions that cause unwanted blood clots. These medicines may also be used during or after surgery to prevent clotting. The right amount and type of anticoagulant can prevent many problems.

Aspirin, usually in doses of 1 tablet every day, can prevent or delay heart attacks and small strokes. Talk to your healthcare provider about the best dose for you. If your provider has told you to take aspirin to help prevent a heart attack, you need to know that taking ibuprofen at the same time--for pain relief, for example--may interfere with the benefits of aspirin for the heart. It may be all right to take both of these medicines, but talk with your healthcare provider about the timing for taking both of them.

Clopidogrel and ticlopidine may also be used to prevent or delay heart attacks and small strokes.

Warfarin is used to treat and prevent blood clots. People with some kinds of artificial heart valves need to take warfarin. Warfarin is also used to treat heart attacks and certain kinds of stroke caused by atrial fibrillation. For more information on warfarin, see:

Warfarin.

Heparin, fondaparinux, and LMWH are used in hospitals or clinics because they work right away. These drugs are used during heart valve surgery, after hip replacement surgery or other surgery, and for serious cases of blood clots and heart attacks. Sometimes these medicines may be continued after your hospital stay and you will be taught how to give yourself the shots or have someone at home give them to you. You may need regular blood tests while you are taking this medicine.

The thrombin inhibitors are used in hospitals to prevent or treat blood clots. Sometimes these medicines are used if you cannot take other heparinlike medicines.

Abciximab, tirofiban, and eptifibatide are usually used for a short time in the hospital after you have had a heart attack or if you need to have coronary angioplasty.

What should I watch out for?

You may need regular testing while you take this medicine to check how the medicine is affecting you. Keep all of your appointments for these tests.

Do not take aspirin unless you are told to by your healthcare provider. Aspirin may make your blood too slow to clot when clotting is needed.

These medicines may cause you to bleed more easily or bleed longer. Because of this risk, there are some precautions that you should take:

Avoid sports and activities that may cause injury. If you fall or are injured, contact your healthcare provider right away. An injury could cause serious internal bleeding without your knowing about it.
If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist that you are taking this medicine.

Many other medicines may affect the action of these medicines. Tell your healthcare provider and pharmacist about any other prescription or nonprescription medicines, vitamins, or natural remedies you are taking. Sometimes, there may be some conditions for which combining a daily low dose of aspirin with warfarin may be appropriate. Talk with your healthcare provider about this. Do not take any other medicines unless your healthcare provider approves. Also, do not stop taking any medicines without talking to your healthcare provider or pharmacist.

If you are taking any of these medicines, closely follow your healthcare provider's instructions about doses and testing. In order for these medicines to help you without causing serious side effects, such as bleeding, they must be used properly and you must follow the precautions concerning their use exactly.

When should I call my healthcare provider?

If you are taking any of these medicines and have any of the following side effects, contact your provider right away:

blood in your urine or vomit
black or tarry stools
unusual bleeding or bruising
worsening chest pain
trouble breathing.