The drug Clopidogrel (Plavix) was released in 1993 to inhibit platelet aggregation. Platelets are the  cell fragments that are involved in the cellular mechanisms that lead to the formation of blood clots. Platelets can be activated as a result of contact with collagen (connective tissue), thrombin (coagulation protein), or ADP. The activation of platelets leads to the production of many coagulation factors which assist in blood clotting. The platelets can form a haemostatic plug in the blood vessel through adhering to endothelial cells lining the blood vessel. Antiplatelet drugs such as clopidogrel are widely used in the prevention of cardiovascular disease.