Patient education: Anticoagulant medicines – Uses and kinds (The Basics)

What are anticoagulants? — 

These are medicines that decrease blood clotting. They are used to:

●Keep clots from growing bigger and blocking blood vessels

●Help prevent new clots from forming

These medicines do not dissolve clots that have already formed. Over time, the body will slowly remove the clot, but this can take months.

Preventing clots is important because it lowers the chances of serious problems like blood clots in the lungs, strokes, and heart attacks.

Anticoagulants are also sometimes called "blood thinners." But they do not actually thin the blood.

What is a blood clot? — 

After an injury, if there is a hole in a blood vessel, parts of the blood can patch the hole until the blood vessel seals. Sometimes, these parts of the blood can react when there is no injury and make a clot. A clot can block the blood from flowing to the parts of the body where it needs to go.

Blood clots can form anywhere. One place this happens is in the veins of the leg. A blood clot in a leg vein is called a "deep vein thrombosis," or "DVT." It can cause swelling and pain. Blood clots can also happen in the arm. Or they can form in the heart, in people with a condition called "atrial fibrillation," or "A-fib."

Blood clots can break off, travel to another part of the body, and block the flow of blood there. If a blood clot travels from the leg to the lungs, it is called a "pulmonary embolism," or "PE." If a PE is large, it can make you pass out or stop breathing. If a blood clot travels from the heart to the brain, it can cause a stroke.

Nothing can completely prevent all blood clots. But anticoagulant medicines can make clots less likely to form.

Why do I need an anticoagulant? — 

Doctors prescribe an anticoagulant medicine when there is an increased chance of forming harmful blood clots. Examples include:

●A-fib – This is a heart rhythm problem where the blood does not flow through the heart normally. If this happens, a blood clot can form. Sometimes, a clot in the heart can break off and travel to the brain and cause a stroke. An anticoagulant helps lower the chances of a blood clot forming inside the heart.

●Surgery – When parts of the body are healing and not moving after surgery, blood clots can form. Preventing clots is especially important after certain surgeries, like a hip or knee replacement. But clots can happen after many types of surgery.

●A mechanical (metal) heart valve – The metal in the valve makes blood more likely to clot in the heart. Sometimes, a clot in the heart can break off, travel to the brain, and cause a stroke. An anticoagulant helps lower the chances of a blood clot forming inside the heart.

●Other reasons – Certain types of cancer, medicines, and other medical conditions can sometimes increase the risk of blood clots.

Doctors also prescribe an anticoagulant for people who have already had a clot. The medicine can prevent clots from getting bigger and prevent more clots from forming. Examples include a:

●Stroke from A-fib

●Clot in the leg or lung (DVT or PE)

●Clot in another body part

What are some of the different anticoagulants? — 

Many are oral medicines, meaning they come as pills or capsules you take by mouth. Examples include:

●Apixaban (brand name: Eliquis)

●Dabigatran (brand name: Pradaxa)

●Edoxaban (brand names: Savaysa, Lixiana)

●Rivaroxaban (brand name: Xarelto)

●Warfarin (brand name: Jantoven, also called Coumadin in some places)

Before prescribing an anticoagulant, your doctor will talk with you about your situation and preferences. Your options depend on why you need an anticoagulant as well as your other health conditions.

In some cases, doctors prescribe an anticoagulant that comes as an injection (shot) instead. The shot is given under the skin. Examples include:

●"Low molecular weight heparin," such as enoxaparin (brand name: Lovenox) or dalteparin (brand name: Fragmin)

●Fondaparinux (brand name: Arixtra)

People being treated in the hospital might get an anticoagulant called heparin through an IV. (An IV is a thin tube that goes into a vein.)

Are there other types of medicines used for blood clots? — 

Yes:

●For some people, doctors might prescribe an "antiplatelet" medicine. This can be taken along with or instead of an anticoagulant. Antiplatelet medicines work by stopping blood cells called "platelets" from sticking together and forming clots. They are used for many conditions where clots can form, including heart attack, angina, stroke, and heart procedures. Examples include low-dose aspirin, clopidogrel (brand name: Plavix), and ticagrelor (brand name: Brilinta).

●For people with very large or life-threatening blood clots, doctors might prescribe a "thrombolytic" medicine. These are also called "clot-busting" medicines because they dissolve the clot. They are given in the hospital because they have a higher risk of causing bleeding. Alteplase, or "tPA," is an example.

What are the differences between the oral anticoagulants? — 

The table answers many common questions about the differences (table 1). Some of the main differences include:

●What health problems they are used for

●Whether they are taken once a day or twice a day

●Whether you need to change your diet

●Whether you need regular blood tests

●What to do if you miss a dose

●The risk of bleeding

What are the risks of taking anticoagulants? — 

The main risk is bleeding. Serious bleeding is not common, but you can take steps to stay safe. For example, you can do things to lower your chances of falling or getting injured.

More information about how to stay safe while taking an anticoagulant is available separately. Ask your doctor for the UpToDate handout on "How to take anticoagulants safely."

For more detailed information about your medicines, ask your doctor or pharmacist for the patient drug information handout from UpToDate. It explains how to use each medicine, describes its possible side effects, and lists other medicines or foods that can affect how it works.

More on this topic

Patient education: How to take anticoagulants safely (The Basics)
Patient education: Lowering the risk of a blood clot (The Basics)
Patient education: Managing increased bleeding risk (The Basics)
Patient education: Deep vein thrombosis (blood clot in the leg) (The Basics)
Patient education: Deep vein thrombosis (blood clot in the arm) (The Basics)
Patient education: Pulmonary embolism (blood clot in the lung) (The Basics)
Patient education: Atrial fibrillation (The Basics)
Patient education: Medicines for atrial fibrillation (The Basics)
Patient education: Stroke (The Basics)
Patient education: Heart attack (The Basics)
Patient education: Prosthetic valves (The Basics)
Patient education: Prothrombin time and INR (PT/INR) (The Basics)
Patient education: Warfarin and your diet (The Basics)
Patient education: Coping with high drug prices (The Basics)

Patient education: Warfarin (Beyond the Basics)
Patient education: Deep vein thrombosis (DVT) (Beyond the Basics)
Patient education: Pulmonary embolism (Beyond the Basics)
Patient education: Atrial fibrillation (Beyond the Basics)
Patient education: Heart attack (Beyond the Basics)
Patient education: Coping with high prescription drug prices in the United States (Beyond the Basics)