An anticoagulant is a substance that prevents coagulation (clotting) of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis equipment.
Contents
|
Anticoagulants reduce blood clotting. This prevents deep vein thrombosis, pulmonary embolism, myocardial infarction and stroke.
These oral anticoagulants are a class of pharmaceuticals that antagonize the effects of vitamin K1. Examples include warfarin. It takes at least 48 to 72 hours for the anticoagulant effect to develop. Where an immediate effect is required, heparin must be given concomitantly. These anticoagulants are used to treat patients with deep-vein thrombosis (DVT), pulmonary embolism (PE), atrial fibrillation (AF), and mechanical prosthetic heart valves.
Patients aged 80 years or more may be especially susceptible to bleeding complications with a rate of 13 bleeds per 100 person-years.[1]
These oral anticoagulants are used widely as poisons for mammalian pests, especially rodents. (For details, see rodenticide and warfarin.)
Depletion of vitamin K by coumadin therapy increases risk of arterial calcification and heart valve calcification, especially if too much vitamin D is present.[2]
Heparin is a biological substance, usually made from pig intestines. It works by activating antithrombin III, which blocks thrombin from clotting blood. Heparin can be used in vivo (by injection), and also in vitro to prevent blood or plasma clotting in or on medical devices. Vacutainer brand test tubes containing heparin are usually colored green.
In March 2008 major recalls of Heparin were announced by pharmaceuticals due to a suspected and unknown contamination of the raw Heparin stock imported from China.[4][5] The contaminant was later found to be a non-naturally occurring compound called oversulfated chondroitin sulfate.[6] The U.S. Food and Drug Administration was quoted as stating that at least 19 deaths were believed linked to a raw Heparin ingredient imported from the People's Republic of China, and that they had also received 785 reports of serious injuries associated with the drug’s use. According to the New York Times: 'Problems with heparin reported to the agency include difficulty breathing, nausea, vomiting, excessive sweating and rapidly falling blood pressure that in some cases led to life-threatening shock'.
Low molecular weight heparin is a more highly processed product that is useful as it does not require monitoring of the APTT coagulation parameter (it has more predictable plasma levels) and has fewer side effects.
Drugs such as rivaroxaban and apixaban work by inhibiting Factor Xa directly (unlike the heparins and fondaparinux, which work via antithrombin activation).
Another type of anticoagulant is the direct thrombin inhibitor.[7] Current members of this class include the bivalent drugs hirudin, lepirudin, and bivalirudin; and the monovalent drugs argatroban and dabigatran. An oral direct thrombin inhibitor, ximelagatran (Exanta) was denied approval by the Food and Drug Administration (FDA) in September 2004 [1] and was pulled from the market entirely in February 2006 after reports of severe liver damage and heart attacks. [2] In November 2010 Dabigatran was approved by the FDA to treat Atrial Fibrillation.
Many other anticoagulants exist, for use in Research & Development, and more or less uses as drug candidates or diagnostics
Food supplements with blood thinning effect include Nattokinase and Lumbrokinase
Therapeutic uses of anticoagulants include atrial fibrillation, pulmonary embolism (PE), deep vein thrombosis (DVT), or venous thromboembolism (VTE), congestive heart failure, stroke, myocardial infarction, genetic or acquired hypercoagulability
Laboratory instruments, test tubes, blood transfusion bags, and medical and surgical equipment will get clogged up and become nonoperational if blood is allowed to clot. Chemicals can be added to stop blood clotting. Apart from heparin, most of these chemicals work by binding calcium ions, preventing the coagulation proteins from using them.
For the meaning of more colors, see Vacutainer#including coagulants.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||