![]() ![]() By both mechanisms, ADP-mediated aggregation becomes inhibited. Ticagrelor directly but reversibly binds the P2Y12 receptor. Ĭlopidogrel and prasugrel are prodrugs that irreversibly block P2Y12 receptors on platelets after undergoing conversion to their respective active metabolites. Oral low dose aspirin is given preventatively for ischemic stroke and cardiovascular events. ![]() ![]() This class irreversibly inhibits COX-1 preventing TXA2, which is essential for platelet aggregation. The most widely used antiplatelet drugs are cyclooxygenase (COX) inhibitors, such as aspirin. While the final common pathway is platelet inhibition, there are several different mechanisms that antiplatelet agents can utilize. Mediators including thromboxane A2, adenosine diphosphate (ADP), thromboxane A2 (TXA2), and cAMP activate platelets, and activation of GPIIb/IIIa receptors promote platelet aggregation. Simultaneously, collagen also binds von Willebrand factor (vWF) to activate platelets via glycoprotein (GP) Ia/IIa and GP IV receptors. Underlying collagen interacts with tissue factor (TF) to trigger the clotting cascade, activating thrombin, which contributes to platelet adhesion at the injury site. Under physiological conditions, platelets are activated by a series of intracellular signals when vascular endothelium is damaged. Salicylates are only briefly mentioned here, primarily in comparing various mechanisms of antiplatelet drugs. As such, a separate monograph specifically devoted to salicylate toxicity is available. When compared to individuals not taking antiplatelet medications, patients on an antiplatelet agent have a 1.5 times greater risk of bleeding, and this increases when taking additional antiplatelet agents. Given the relatively narrow pharmacologic actions of antiplatelet drugs, toxicity primarily confines itself to an increased risk of hemorrhage. Despite a variety of pharmacologic actions, all antiplatelet drugs inhibit platelet activation and aggregation, lowering atherothrombotic related events. ![]() These agents are used to decrease major adverse events due to acute coronary syndromes, peripheral vascular disease, and stroke. As the prevalence of cardiovascular disease (CVD) escalates worldwide, so does the use of antiplatelet medications in its management. ![]()
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