Normally, there is a delicate balance between coagulation and fibrinolysis that prevents both thrombosis and hemorrhage from occurring1,2. If the balance alters in favor of coagulation, an event of thrombosis (blood clot) will result. Anticoagulants can be used to prevent blood clots from forming and to keep existing clots from becoming larger. However, they cannot break down the existing clots like a tissue plasminogen activator (tPA) can. Anticoagulants are commonly used to treat and prevent venous thromboembolism (VTE), including deep vein thrombosis (DVT), pulmonary embolism (PE), and to prevent cardioembolic stroke. It may also be used in acute coronary syndrome (ACS). DVT is a thrombosis that is frequently found in the deep veins of the legs, thighs, and pelvis. A fragment of the clot can break off and circulate to the heart and pump into the lungs. This event is called PE. Cardioembolism stroke can be caused by embolism of thrombotic material forming on the atrial wall, ventricular wall, or left valves of the heart, that detaches and travel to the brain, causing a transient ischemic attack (TIA) or ischemic stroke. Cardioembolic stroke are commonly caused by nonvalvular atrial fibrillation, myocardial infarction (MI), prosthetic valves, and schemic cardiomyopathy.
OVERVIEW OF BLOOD COAGULATION
Blood coagulation occurs when a blood clot forms as a result of endothelial injury, blood stasis, or hypercoagulability1,2. Coagulation process begins with the activation of platelets and the clotting cascade. The activated platelets enhance the activation of coagulation by providing a surface, in which clotting factors can assemble, and by releasing stored clotting factors. This results in the generation of thrombin, which ultimately converts to fibrin that allows for the creation of a stable clot. There are two pathways that lead to fibrin formation, intrinsic and extrinsic pathways. Anticoagulants work by inhibiting the clotting cascade, and reducing and preventing clot formation. Figure 1 below displays the coagulation cascade:
The Coagulation Cascade
Image Reference: Medbullets.com
All anticoagulants can increase bleeding risk, thereby putting patients at risk for increased mortality4. For this reason, they are high alert drugs. Some drugs and herbal products that can increase risk of bleeding due to additive effect when administering concurrently with anticoagulants include other anticoagulants, antiplatelet drugs, NSAIDs, SSRIs, SNRIs, fish oils, garlic, ginger, ginkgo biloba, ginseng, glucosamine, willow bark, grapefruit, policosanol, and more.
Injectable anticoagulants, such as UFH, are used to treat and prevent VTE and ACS1,2,3. The table below provides unfractionated heparin drug information.
Table 1Unfractionated Heparin Drug Information |Favorite Table|Download (.pdf) Table 1 Unfractionated Heparin Drug Information
|Unfractionated Heparin |
|MEDICATION ||DOSING ||DRUG INFORMATION |