Anticoagulants are medicines that increase the time it takes for blood to clot. They are commonly called blood thinners.
There are several different types of anticoagulant. Each type works at a different level on the blood coagulation pathway. Some can be given by mouth; others can only be given by injection.
Anticoagulants may be used to treat blood clots, or in conditions where the risk of blood clots is increased to reduce the risk. Examples of conditions where anticoagulants may be used include:
Anticoagulants may be divided into four main groups: coumarins and indandiones; factor Xa inhibitors; heparins; and direct thrombin inhibitors.
Warfarin is a coumarin, and the only coumarin available in the U.S for human use. It works by limiting the availability of vitamin K, a vitamin that is necessary for the blood coagulation pathway to produce clotting factors II, VII, IX, and X. This decreases the blood’s ability to clot.
Indandiones have a similar way of working to coumarins but they are mainly used for pest control to control rat, mice, and rabbit populations. Examples include pindone and diphacinone.
Coumarins and indandiones may also be called vitamin K antagonists.
| Generic name | Brand name examples |
|---|---|
| warfarin | Coumadin, Jantoven |
Factor Xa inhibitors work on factor Xa in the coagulation cascade, which is responsible for converting the protein prothrombin into thrombin. Factor Xa inhibitors can affect factor Xa within the blood and also within a pre-existing clot.
Factor Xa inhibitors do not require routine monitoring, unlike some other anticoagulants.
| Generic name | Brand name examples |
|---|---|
| apixaban | Eliquis |
| edoxaban | Savaysa |
| fondaparinux | Arixtra |
| rivaroxaban | Xarelto |
The heparins are a group of anticoagulants that consist of unfractionated heparin, low molecular weight heparins, and heparinoids.
Unfractionated heparin (usually just called heparin) needs to be given directly into the blood by intravenous (IV) injection, and inhibits thrombin and factor Xa, factors necessary in the final stages of the blood clotting cascade. Heparin may also be called high molecular weight heparin. Daily monitoring is required with heparin to check the aPTT. The aPTT is the speed at which clotting occurs.
Low molecular weight heparins (LMWH) also work on thrombin and factor Xa; however, they preferentially inactivate factor Xa. Because their anticoagulant response is more predictable, they do not need daily blood monitoring. LMWHs last much longer in the body than heparin and are injected under the skin (subcutaneously). Some people can learn to inject LMWHs at home by themselves.
Heparinoids have a similar action to heparin and are extracted from specific animal and plant tissues or made synthetically. They are usually applied topically and are easily absorbed into the skin where they can reduce small blood clots, reduce inflammation and associated pain and discomfort. Chitin and chondroitin sulfate are also heparinoids.
| Generic name | Brand name examples |
|---|---|
| Unfractionated heparins | |
| heparin | Hep-Lock |
| LMWHs | |
| dalteparin | Fragmin |
| enoxaparin | Lovenox |
| tinzaparin | Discontinued |
| Heparinoids | |
| heparinoid | Hirudoid (not available in the U.S.) |
Direct thrombin inhibitors bind directly to thrombin, inhibiting its action. Direct thrombin inhibitors that need to be given by injection include desirudin which binds to both the active enzymatic site and to exosite 1, and argatroban which binds to the active enzymatic site only. Dabigatran is an oral direct thrombin inhibitor which binds reversibly to the active enzymatic site.
| Generic name | Brand name examples |
|---|---|
| argatroban | Acova |
| bivalirudin | Angiomax |
| dabigatran | Pradaxa |
| desirudin | Iprivask |
| lepirudin | Discontinued in 2012 |
Anticoagulants are considered safe when administered exactly as intended for the recommended duration of time. However, they have been associated with some serious side effects such as:
Warfarin can also interact with certain foods and many commonly used medicines. Regular blood monitoring (international normalized ratio-INR) is necessary because there is a fine line between an effective dose and a toxic one.
For a complete list of severe side effects, please refer to the individual drug monographs.
The more common side effects that have been associated with anticoagulants include:
For a complete list of side effects, please refer to the individual drug monographs.
Data Source:drugs.com
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Heparin is used to prevent blood clots from forming in people who have certain medical conditions or who are undergoing certain medical procedures that increase the chance that clots will form. Heparin is also used to stop the growth of clots that have already formed in the blood vessels, but it cannot be used to decrease the size of clots that have already formed. Heparin is also used in small amounts to prevent blood clots from forming in catheters (small plastic tubes through which medication can be administered or blood drawn) that are left in veins over a period of time. Heparin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.
Data Source:medlineplus.gov
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Potassium is essential for the proper functioning of the heart, kidneys, muscles, nerves, and digestive system. Usually the food you eat supplies all of the potassium you need. However, certain diseases (e.g., kidney disease and gastrointestinal disease with vomiting and diarrhea) and drugs, especially diuretics ('water pills'), remove potassium from the body. Potassium supplements are taken to replace potassium losses and prevent potassium deficiency.
Data Source:medlineplus.gov
Potassium is essential for the proper functioning of the heart, kidneys, muscles, nerves, and digestive system. Usually the food you eat supplies all of the potassium you need. However, certain diseases (e.g., kidney disease and gastrointestinal disease with vomiting and diarrhea) and drugs, especially diuretics ('water pills'), remove potassium from the body. Potassium supplements are taken to replace potassium losses and prevent potassium deficiency.
Data Source:medlineplus.gov
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