Long acting synthetic pentasaccharide that is an antithrombin dependent inhibitor of activated factor X.
Has a specific inhibitory effect on factor Xa activity mediated through plasma anti-thrombin.
A fixed dose subcutaneously once per week is effective prophylaxis against recurrent venous thromboembolism but is associated with a greater risk of bleeding than with vitamin K antagonists.
Has a terminal half-life of about 66 days, allowing once weekly subcutaneous injection therapy.
No laboratory monitoring necessary.
In patients with venous thromboembolism who completed 6 months of anticoagulant therapy, a further 6 months of prophylactic therapy with Idraparinux reduced the frequency of recurrent thromboembolism to 1% compared to 3.7% in a placebo group. (van Gogh Investigators)
Associated with an excess of major bleeding (1.9%), including fatal hemorrhage, compared to placebo (0%) when given as a 6 month extension of thromboprophylaxis.
Studies have shown equivalent efficacy for treatment of deep vein thrombosis compared to standard therapy, but with improved quality of life.
Idraparinux without initial low molecular weight heparin is less effective than with standard therapy in a parallel study of patients with pulmonary embolus ( Van Gogh Investigators).