Synonyms

Platelet anti-aggregant drugs

Definition

Antiplatelet therapy uses specific pharmacological agents (antiplatelet drugs) to inhibit the ability of platelets to clump together to form blood clots or thromboses, primarily in arteries. Antiplatelet therapy is commonly used in people with atherosclerosis (narrowing of the arteries). Platelets are naturally occurring cells (actually, portions of cells) that circulate in the blood. They clump, or aggregate, under certain conditions to initiate the formation of blood clots. These platelet clumps are then further bound together by the protein, fibrin. Together, the fibrin and the platelet clump comprise the thrombus or blood clot. Thrombi are useful in that they stop bleeding in normal circumstances. When there is a break in an artery, allowing blood to leave the vessel, platelets become activated by attaching to the wall of the blood vessel at the site of the bleeding and by attracting fibrin and other coagulation factors to the area to stop the bleeding. However, if the blood clot forms inside the artery, it can block the flow of blood to the tissue that is supplied by the artery, which can result in tissue damage. A clot forming in the coronary artery causes ischemic heart disease (which may present as angina or myocardial infarction), and when the blood clot forms in the carotid or cerebral arteries, it may cause a stroke.

Current Knowledge

Many studies have demonstrated the effectiveness of aspirin and other antiplatelet agents in preventing heart attack and stroke. This favorable effect is based on the ability of these agents to inhibit the chemicals that cause platelets to clump together initiating blood clot formation.

Aspirin is the prototypical antiplatelet agent. Other currently available antiplatelet agents include ticlopidine (Ticlid ®), clopidogrel (Plavix®), and dipyridamole (Persantine ®). Recently, a newer antiplatelet drug, ticagrelor (BRILINTA®), became available. Occasionally, the drugs are used in combination with each other or with anticoagulants. The most common side effect of all of these medications is bleeding.

See Also