Clopidogrel Bisulfate (Plavix)

Three types of blood cells exist in the human body: red blood cells, white blood cells, and platelets. Red blood cells, 45% of the blood, transport oxygen from the lungs to other body parts. White cells, less than 1% of the blood, defend us against bacterial and viral invasions. Platelets, also less than 1% of the blood (55% of the remaining blood is plasma), are small cell fragments that are involved in helping the blood clot, a process known as blood coagulation. Coagulation takes place when the enzyme thrombin elicits platelets and fibrin, a blood protein. Without platelets, coagulation at the site of an injury does not occur and uncontrolled bleeding ensues. Individuals with no ability to clot have a genetic condition called hemophilia. These individuals must periodically administer a clotting factor to their blood to prevent constant bleeding. Conversely, thrombosis, the formation of blood clots inside blood vessels, can block coronary arteries and constrict vital oxygen supplies, resulting in a heart attack or stroke. Coronary thrombosis is a life-threatening blood clot in the artery. Deep-vein thrombosis (DVT) is commonly associated with long-distance air travel, when passengers are confined to cramped spaces for many hours. In contrast with thrombosis, in which the clot is stationary, embolus is when an object such as a clot migrates from one part of the body through blood circulation and causes blockage. A pulmonary embolism occurs when emboli travel to the lungs. Approximately 90% of heart attacks and 80% of strokes are caused by blood clots, which kill some 200,000 hospital patients in the US each year. Anticoagulants (blood thinners) are the drugs of choice to prevent and treat both thrombosis and embolism. To date, heparin, warfarin, and aspirin have all been widely used as blood thinners to prevent blood clots from forming. Heparin is one of the oldest medicines still in widespread clinical use. Heparin was extracted in 1916 by Jay McLean from dog’s liver in the laboratories of William Howell at the Johns Hopkins University.