Editing Anticoagulant (section)

===Heparin and derivative substances===
Heparin is the most widely used intravenous clinical anticoagulant worldwide.<ref>{{cite journal | vauthors = Linhardt RJ | title = 2003 Claude S. Hudson Award address in carbohydrate chemistry. Heparin: structure and activity | journal = Journal of Medicinal Chemistry | volume = 46 | issue = 13 | pages = 2551–64 | date = June 2003 | pmid = 12801218 | doi = 10.1021/jm030176m }}</ref> [[Heparin]] is a naturally occurring [[glycosaminoglycan]]. There are three major categories of heparin: unfractionated heparin (UFH), low molecular weight heparin (LMWH), and ultra-low-molecular weight heparin (ULMWH).<ref name="Heparin and anticoagulation">{{cite journal | vauthors = Onishi A, St Ange K, Dordick JS, Linhardt RJ | title = Heparin and anticoagulation | journal = Frontiers in Bioscience | volume = 21 | issue = 7 | pages = 1372–92 | date = June 2016 | pmid = 27100512 | doi = 10.2741/4462 }}</ref>  Unfractionated heparin is usually derived from [[pig]] intestines and bovine lungs.<ref>{{cite journal | vauthors = Casu B, Naggi A, Torri G | title = Re-visiting the structure of heparin | journal = Carbohydrate Research | volume = 403 | pages = 60–68 | date = February 2015 | pmid = 25088334 | doi = 10.1016/j.carres.2014.06.023 }}</ref> UFH binds to the enzyme inhibitor [[antithrombin]] III (AT), causing a conformational change that results in its activation.<ref>{{cite journal | vauthors = Seo Y, Andaya A, Leary JA | title = Preparation, separation, and conformational analysis of differentially sulfated heparin octasaccharide isomers using ion mobility mass spectrometry | journal = Analytical Chemistry | volume = 84 | issue = 5 | pages = 2416–23 | date = March 2012 | pmid = 22283665 | pmc = 3296823 | doi = 10.1021/ac203190k }}</ref> The activated AT then inactivates [[factor Xa]], [[thrombin]], and other coagulation factors.<ref>{{cite journal | vauthors = Allingstrup M, Wetterslev J, Ravn FB, Møller AM, Afshari A | title = Antithrombin&nbsp;III for critically ill patients: a systematic review with meta-analysis and trial sequential analysis | journal = Intensive Care Medicine | volume = 42 | issue = 4 | pages = 505–20 | date = April 2016 | pmid = 26862016 | pmc = 2137061 | doi = 10.1007/s00134-016-4225-7 }}</ref> Heparin can be used ''[[in vivo]]'' (by injection), and also ''[[in vitro]]'' to prevent blood or plasma clotting in or on medical devices. In [[venipuncture]], [[Vacutainer]] brand blood collecting tubes containing heparin usually have a green cap.<ref>{{cite journal |vauthors=Brizzee L, Stone A, Palmer MC |title=False lithium toxicity secondary to lithium heparin test tube: A case report and review |journal=Ment Health Clin |volume=10 |issue=3 |pages=90–94 |date=May 2020 |pmid=32420006 |pmc=7213950 |doi=10.9740/mhc.2020.05.090 }}</ref>

====Low molecular weight heparin (LMWH)====
[[Low molecular weight heparin]] (LMWH) is produced through a controlled depolymerization of unfractionated heparin.<ref name="Heparin and anticoagulation"/> LMWH exhibits a higher anti-Xa/anti-IIa activity ratio and is useful as it does not require monitoring of the [[APTT]] [[coagulation]] parameter and has fewer side effects.<ref name="Heparin and anticoagulation"/>