Anticoagulant Medications how work?
Anticoagulant medications work by preventing the formation of new blood clots or the extension of existing blood clots. This is accomplished by inhibiting the factors involved in clot formation in one of two ways: preventing clotting factor synthesis or preventing clotting factor activity. Anticoagulant medications are not effective in dissolving existing clots.
Anticoagulant medications should be used with caution in any patient with a potential site for bleeding. Contraindications to the use of anticoagulant medications include patients with known coagulation disorders, peptic ulcer disease, recent surgery, or active bleeding. An overview of anticoagulant medications is provided in the following table.
Anticoagulant medications are indicated for the prevention and treatment of thrombosis and thromboembolic disorders in both the venous and arterial systems (American College of Chest Physicians Antithrombotic Therapy and Prevention of Thrombosis Panel, 2012). Indications for use include:
- Adjunct therapy for acute coronary syndromes (ACS), such as unstable angina and myocardial infarction (MI), including following the administration of thrombolytics or intravenous (IV) antiplatelet agents such as the GP-IIb/IIIa inhibitors. Currently, heparin is recommended for all patients with ST-segment elevation myocardial infarction who are undergoing thrombolytic therapy or percutaneous coronary intervention (PCI). Heparin therapy should begin prior to administering the thrombolytic and continue for 48 to 72 hours after. In PCI, heparin is given one time, immediately before beginning the procedure (Lehne, 2013
- Pulmonary embolism (PE) treatment and prevention in patients with recurrent PEs.
- Deep vein thrombosis (DVT) treatment and prevention; for example, after certain surgical procedures (orthopedic surgeries, such as total knee and total hip replacement), in patients with cancer (Lyman, 2011), and in situations where prolonged bedrest and reduced blood flow (stasis) increase the risk of thrombosis development.
- Treatment and prevention of heparin-induced thrombocytopenia (HIT). Only the anticoagulants Lepirudin and Argatroban are approved by the U.S. Food and Drug Administration (FDA) for the management of HIT.
- Atrial fibrillation (AF) is the most common form of dysrhythmia. It substantially increases the risk of stroke because it allows stasis of blood in the atria, leading to the formation of thrombi (Deglin, Vallerand, & Sanoski, 2011).