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Fondaparinux (trade name Arixtra) is an anticoagulant medication chemically related to low molecular weight heparins. It is marketed by GlaxoSmithKline. A generic version developed by Alchemia is marketed within the US by Dr. Reddy's Laboratories.

Clinical data
Trade namesArixtra
License data
Routes of
ATC code
Legal status
Legal status
Pharmacokinetic data
Protein binding94%
Metabolismrenally excreted unchanged
Elimination half-life17-21 hours
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass1726.77 g/mol g·mol−1
3D model (JSmol)
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Medical usesEdit

Clinically, it is used for the prevention of deep vein thrombosis in patients who have had orthopedic surgery as well as for the treatment of deep vein thrombosis and pulmonary embolism.

Fondaparinux is similar to enoxaparin in reducing the risk of ischemic events at nine days, but it substantially reduces major bleeding and improves long-term mortality and morbidity.[1]

It has been investigated for use in conjunction with streptokinase.[2]


Fondaparinux is given subcutaneously daily.

Comparison to other agentsEdit

One potential advantage of fondaparinux over LMWH or unfractionated heparin is that the risk for heparin-induced thrombocytopenia (HIT) is substantially lower. Furthermore, there have been case reports of fondaparinux being used to anti-coagulate patients with established HIT as it has no affinity for PF4. However, its renal excretion precludes its use in patients with renal dysfunction.

Unlike direct factor Xa inhibitors, it mediates its effects indirectly through antithrombin III, but unlike heparin, it is selective for factor Xa.[3]


Mechanism of actionEdit

Fondaparinux is a synthetic pentasaccharide factor Xa inhibitor. Fondaparinux binds antithrombin and accelerates its inhibition of factor Xa.

Apart from the O-methyl group at the reducing end of the molecule, the identity and sequence of the five monomeric sugar units contained in fondaparinux is identical to a sequence of five monomeric sugar units that can be isolated after either chemical or enzymatic cleavage of the polymeric glycosaminoglycans heparin and heparin sulfate (HS). Within heparin and heparin sulfate this monomeric sequence is thought to form the high-affinity binding site for the anti-coagulant factor antithrombin (AT). Binding of heparin or HS to AT has been shown to increase the anti-coagulant activity of antithrombin 1000 fold. In contrast to heparin, fondaparinux does not inhibit thrombin.



  • GlcNS6S = 2-deoxy-6-O-sulfo-2-(sulfoamino)-α-D-glucopyranoside
  • GlcA = β-D-glucopyranuronoside
  • GlcNS3,6S = 2-deoxy-3,6-di-O-sulfo-2-(sulfoamino)-α-D-glucopyranosyl
  • IdoA2S = 2-O-sulfo-α-L-idopyranuronoside
  • GlcNS6SOMe = methyl-O-2-deoxy-6-O-sulfo-2-(sulfoamino)-α-D-glucopyranoside

The sequence of monosaccharides is D-GlcNS6S-α-(1,4)-D-GlcA-β-(1,4)-D-GlcNS3,6S-α-(1,4)-L-IdoA2S-α-(1,4)-D-GlcNS6S-OMe, as shown in the following structure:


  1. ^ Fifth Organization to Assess Strategies in Acute Ischemic Syndromes Investigators; Yusuf, S.; Mehta, S. R.; Chrolavicius, S.; Afzal, R.; Pogue, J.; Granger, C. B.; Budaj, A.; Peters, R. J.; Bassand, J. P.; Wallentin, L.; Joyner, C.; Fox, K. A. (2006-04-06). "NEJM -- Comparison of Fondaparinux and Enoxaparin in Acute Coronary Syndromes" (PDF). New England Journal of Medicine. 354 (14): 1464–1476. doi:10.1056/NEJMoa055443. hdl:2437/113091. PMID 16537663.
  2. ^ Peters RJ, Joyner C, Bassand JP, et al. (February 2008). "The role of fondaparinux as an adjunct to thrombolytic therapy in acute myocardial infarction: a subgroup analysis of the OASIS-6 trial". Eur. Heart J. 29 (3): 324–31. doi:10.1093/eurheartj/ehm616. PMID 18245119.
  3. ^ "". Retrieved 2009-01-23.

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