Final answer:
Heparin is an anticoagulant used to prevent blood clot formation in patients at risk, administered either intravenously or subcutaneously but not orally. It works by inactivating factors involved in blood coagulation, such as factor X, and is distinct from thrombolytic agents, which break down clots, and antiplatelet drugs, which prevent platelet aggregation.
Step-by-step explanation:
Heparin is an anticoagulant, which is a substance that opposes coagulation. It is often administered therapeutically to patients, such as those undergoing surgery, to prevent the formation of blood clots. Heparin works by inactivating specific factors in the blood coagulation process, such as factor X and by opposing the conversion of prothrombin (factor II) to thrombin. This helps to maintain a normal, clot-free condition of the blood within the vessels. Heparin is given intravenously (IV) or subcutaneously (SQ) but not orally (PO), since it would be broken down in the gastrointestinal tract, rendering it ineffective.
Other medications, such as Rivaroxaban (Xarelto), Dabigaran (Pradaxa), Apixaban (Eliquis), and Warfarin (Coumadin), are also anticoagulants used for preventing blood clot formation. On the other hand, a class of drugs known as thrombolytic agents is used for breaking down existing clots, not preventing them. Vasodilators like bradykinin are substances that dilate blood vessels to increase blood flow, while antiplatelet drugs prevent platelets from clumping together to form clots.