View source for Unstable angina non ST elevation myocardial infarction factor Xa inhibitors therapy

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{{Unstable angina / NSTEMI}}
{{CMG}}; '''Associate Editors-in-Chief:''' [[Varun Kumar]], M.B.B.S.; [[Lakshmi Gopalakrishnan]], M.B.B.S.; Smita Kohli, M.D.

==Overview==
Factor Xa inhibitors are a class of anticoagulants which act by inhibiting factor Xa, which is a common factor for both the intrinsic and extrinsic pathways of the coagulation cascade. 

==Factor Xa Inhibitors==
[[Fondaparinux]] is the prototype in this class of drug which is an indirect Xa inhibitor that requires antithrombin for its action. 

====Clinical Trial Data====
*The ''OASIS 5 and 6'' trials<ref name="pmid18955665">{{cite journal |author=Mehta SR, Boden WE, Eikelboom JW, Flather M, Steg PG, Avezum A, Afzal R, Piegas LS, Faxon DP, Widimsky P, Budaj A, Chrolavicius S, Rupprecht HJ, Jolly S, Granger CB, Fox KA, Bassand JP, Yusuf S |title=Antithrombotic therapy with fondaparinux in relation to interventional management strategy in patients with ST- and non-ST-segment elevation acute coronary syndromes: an individual patient-level combined analysis of the Fifth and Sixth Organization to Assess Strategies in Ischemic Syndromes (OASIS 5 and 6) randomized trials |journal=[[Circulation]] |volume=118 |issue=20 |pages=2038–46 |year=2008 |month=November |pmid=18955665 |doi=10.1161/CIRCULATIONAHA.108.789479 |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=18955665 |accessdate=2011-04-11}}</ref> evaluated the use of [[fondaparinux]] in [[ACS]] and compared it with a [[heparin]]-based strategy. Results showed that compared to heparin based strategy, fondaparinux reduced mortality, ischemic events, and major bleeding across the full spectrum of [[acute coronary syndromes]] and was associated with a more favorable net clinical outcome in patients undergoing either an invasive or a conservative management strategy. 
*The ''OASIS-5'' trial<ref name="pmid17964037">{{cite journal |author=Mehta SR, Granger CB, Eikelboom JW, Bassand JP, Wallentin L, Faxon DP, Peters RJ, Budaj A, Afzal R, Chrolavicius S, Fox KA, Yusuf S |title=Efficacy and safety of fondaparinux versus enoxaparin in patients with acute coronary syndromes undergoing percutaneous coronary intervention: results from the OASIS-5 trial |journal=[[Journal of the American College of Cardiology]] |volume=50 |issue=18 |pages=1742–51 |year=2007 |month=October |pmid=17964037 |doi=10.1016/j.jacc.2007.07.042 |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(07)02494-1 |accessdate=2011-04-11}}</ref> specifically compared [[fondaparinux]], administered at a relatively low dose, 2.5 mg subcutaneously, once daily with standard-dose [[enoxaparin]] in 20,078 patients with high-risk [[UA]]/[[NSTEMI]]. The rates of death, [[MI]], or refractory [[ischemia]] throughout the first 9 days were similar with [[fondaparinux]] and [[enoxaparin]]. Of note, however, the rate of major bleeding was almost 50 percent lower in the fondaparinux arm. By 30 days, mortality was significantly lower in the fondaparinux arm. However, in the subset of patients undergoing [[PCI]], fondaparinux was associated with more than a threefold increased risk of catheter-related thrombi. 

====Disadvantage of Factor Xa Inhibitors====
*[[Fondaparinux]] lacks a protamine-binding domain, hence it is not possible to reverse the effect with [[protamine]]. In the event of bleeding, discontinuation of their administration and, if needed, transfusion of coagulation factors (e.g., [[fresh-frozen plasma]]) is required.

==References==
{{reflist|2}}

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