Blood clot drugs

Physiological responses to prostaglandins encompass a variety of effects Some prostaglandins relax bronchial muscle others contract it Some stimulate uterine con tractions and have been used to induce therapeutic abortions PGEj dilates blood vessels and lowers blood pressure it inhibits the aggregation of platelets and offers promise as a drug to reduce the formation of blood clots... 

Tranexamic acid, a drug useful against blood clotting, is prepared commercially from p-methylbenzonitrile. formulate Lhe steps likely to be used in the synthesis. (Don t worry about cis-trans isomers heating to 300 °C interconverts the isomers.)... 

Although the exact action of the thrombolytic dragp is slightly different, these drugs break down fibrin clots by converting plasminogen to plasmin (fibrinolysin). Plasmin is an enzyme that breaks down the fibrin of a blood clot. This reopens blood vessels after their occlusion and prevents tissue necrosis. 

These drugs are used to treat an acute MI by lysing (dissolving) a blood clot in a coronary artery. These drugp are also effective in lysing clots causing PE and DVT. Urokinase is also used to treat PE and to clear IV... 

Another vasoactive substance produced by the endothelium is thromboxane A2 (TxA2). Normally, small amounts of TxA2 are released continuously however, increased synthesis appears to be associated with some cardiac diseases. Synthesized from arachidonic acid, a plasma membrane phospholipid, TxA2 is a potent vasoconstrictor. Furthermore, this substance stimulates platelet aggregation, suggesting that it plays a role in thrombotic events such as myocardial infarction (heart attack). Nonsteroidal anti-inflammatory drugs such as aspirin and ibuprofen block formation of TxA2 and reduce formation of blood clots. 

Platelets play a role in each of the mechanisms of normal hemostasis vasoconstriction, formation of the platelet plug, and blood coagulation. However, they are also involved in pathological processes that lead to atherosclerosis and thrombosis (formation of a blood clot within the vascular system). Antiplatelet drugs interfere with platelet function and are used to prevent the development of atherosclerosis and formation of arterial thrombi. 

Plasma-derived antithrombin concentrates have been used medically since the 1980s for the treatment of hereditary and acquired antithrombin deficiency. Hereditary (genetic) deficiency is characterized by the presence of little/no native antithrombin activity in plasma and results in an increased risk of inappropriate blood clot/emboli formation. Acquired antithrombin deficiency can be induced by drugs (e.g. heparin and oestrogens), liver disease (decreased antithrombin... 

In apoptosis a series of events takes place in an orderly sequence involving the activation of various proteases which are called caspases, for cysteine and aspartate proteases. Several distinct caspases act in a cascade vaguely reminiscent of the blood-clotting cascade of complement proteins. If one wishes to interfere with the apoptotic process, then one strategy would be to develop drugs that inhibit various caspases, a current effort underway in the pharmaceutical industry. 

In addition to erythrocytes, blood contains white blood cells, called leukocytes, of several types, and platelets, also called thrombocytes, which control blood clotting. Hematopoiesis (from the Greek, haimo, for blood, and poiein for to make ) is the process by which the elements of the blood are formed. The marrow of bone contains so-called stem cells which are immature predecessors of these three types of blood cells. Chemicals that are toxic to bone marrow can lead to anemia (decreased levels of erythrocytes), leukopenia (decreased numbers of leukocytes), or thrombocytopenia. Pancytopenia, a severe form of poisoning, refers to the reduction in circulatory levels of all three elements of the blood. One or more of these conditions can result from sufficiently intense exposure to chemicals such as benzene, arsenic, the explosive trinitrotoluene (TNT), gold, certain drugs, and ionizing radiation. Health consequences can range... 

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