fondaparinux brands

Molecular formula: C31H53N3O49S8

The antithrombotic activity of fondaparinux is the result of ATIII-mediated selective inhibition of Factor Xa. By selectively binding to ATIII, Fondaparinux potentiates (about 300 times) the neutralization of Factor Xa by ATIII. Neutralization of Factor Xa interrupts the blood coagulation cascade and thus inhibits thrombin formation and thrombus development. It is thought that fondaparinux is unlikely to induce thrombocytopenia via a heparin-induced thrombocytopenia (HIT)-like mechanism given its chemical structure. As a result, fondaparinux has been used as an alternative anticoagulant in heparin-induced thrombocytopenia (HIT) patients. However, it is important to note that rare cases of HIT have been reported in patients treated with fondaparinux. Antithrombin III generally neutralizes coagulation factor Xa, thrombin, and other coagulation factors, but these reactions are slow in the absence of heparin or fondaparinux. Fondaparinux accelerates the rate at which antithrombin neutralizes factor Xa by inducing a conformational change in antithrombin. This conformational change increases the affinity of antithrombin III for factor Xa, a key enzyme in the coagulation cascade. With fondaparinux therapy, anticoagulation appears to result from rapid inhibition of factor Xa by antithrombin III (about 300-fold greater than innate activity), which inhibits the conversion of prothrombin to thrombin and subsequent thrombus formation. Unlike heparin, which interacts with many plasma components, fondaparinux binds selectively to antithrombin III. Because of its small molecular size, fondaparinux cannot bind simultaneously to antithrombin III and thrombin and therefore is unable to inactivate thrombin itself. At the recommended dosage, fondaparinux does not affect fibrinolytic activity and cannot lyse established thrombi. Fondaparinux generally does not affect platelet function or global clotting function tests (eg, prothrombin time [PT], bleeding time, activated partial thromboplastin time [aPTT]) when administered at the recommended dosage. The antithrombotic activity of fondaparinux sodium is the result of antithrombin III (ATIII)-mediated selective inhibition of Factor Xa. By selectively binding to ATIII, fondaparinux sodium potentiates (about 300 times) the innate neutralization of Factor Xa by ATIII. Neutralization of Factor Xa interrupts the blood coagulation cascade and thus inhibits thrombin formation and thrombus development. Fondaparinux sodium does not inactivate thrombin (activated Factor II) and has no known effect on platelet function. At the recommended dose, fondaparinux sodium does not affect fibrinolytic activity or bleeding time. The limitations of conventional anticoagulants have stimulated the development of new anticoagulants. The central position of factor Xa (FXa) at the junction of the intrinsic and extrinsic pathways in the coagulation cascade means that direct and indirect FXa inhibitors have increasingly changed antithrombotic strategies. FXa inhibitors potently and selectively inhibit thrombin formation rather than thrombin activity. Direct FXa inhibitors may directly bind to FXa, whereas indirect inhibitors are dependent on antithrombin. Direct inhibitors may bind free FXa and, in contrast to indirect inhibitors, FXa within the prothrombinase complex or within clots as well. Fondaparinux is the prototype indirect FXa inhibitor and has been extensively studied in the prevention and treatment of thromboembolic diseases, including acute coronary syndromes. ... Fondaparinux is a selective inhibitor of activated factor X. Its structure is the copy of the heparin pentasaccharide sequence, the shortest chain required for antithrombin inhibition of activated factor X without antithrombin action. Fondaparinux has no effect on coagulation tests and does not bind to platelet factor 4 or promote heparin-induced thrombocytopenia. Fondaparinux inhibits thrombin generation and the growth of thrombi in in vitro and in vivo mo

Source: PubChem (NCBI) · compound 5282448