Lepirudin

Lepirudin is a recombinant hirudin formed by 65 amino acids that acts as a highly specific and direct thrombin inhibitor. Natural hirudin is an endogenous anticoagulant found in Hirudo medicinalis leeches. Lepirudin is produced in yeast cells and is identical to natural hirudin except for the absence of sulfate on the tyrosine residue at position 63 and the substitution of leucine for isoleucine at position 1 (N-terminal end). Lepirudin is used as an anticoagulant in patients with heparin-induced thrombocytopenia (HIT), an immune reaction associated with a high risk of thromboembolic complications. HIT is caused by the expression of immunoglobulin G (IgG) antibodies that bind to the complex formed by heparin and platelet factor 4. This activates endothelial cells and platelets and enhances the formation of thrombi. Bayer ceased the production of lepirudin (Refludan) effective May 31, 2012.