Preventing blood clotting
Blood clotting is essential for the body to function properly, and an impaired coagulation system can be fatal in some cases. Nevertheless, it can also be excessive and needs to be toned down. This is seen in some congenital disorders, autoimmune conditions like antiphospholipid syndrome, or can even be a result of some cancers. Blood vessels may also be diseased by atherosclerosis and their walls become so rough that anticoagulation is needed to prevent clotting within them. In some cases, artificial heart valves or blood vessel grafts may need anticoagulation since their surface is rougher than their natural counterparts.
Anticoagulation can be achieved by 2 main mechanisms; the first is antiplatelet drugs which don’t act directly on the coagulation system, but rather impair platelet function. The main drugs used for that purpose are Aspirin and Clopidogrel. They prevent platelets from adhering to the vessel wall and aggregating. The second, more effective method involves direct action on the coagulation factors. Common drugs used for that purpose include Warfarin which acts on vitamin K, which is needed to produce 4 essential coagulation factors: II, VII, IX, and X. Warfarin is the most widely used anticoagulant because it doesn’t need injections. Other anticoagulants include heparin, which acts by increasing the activity of the natural anticoagulant, antithrombin III, while low molecular weight heparin acts on factor X. There are some drugs like Warfarin that need regular monitoring through some tests to make sure that anticoagulation is controlled; otherwise, bleeding may be severe.