Bivalirudin is an inhibitor of α- and ζ-thrombin (Kis = 2.56 and 1.84 nM, respectively), enzymes that exhibit high fibrinogen-clotting activities.1 It is selective for α- and ζ-thrombin, lacking activity at trypsin and γ-thrombin, which lacks clotting activity, at a >1,000-fold excess of bivalirudin. Bivalirudin inhibits α-thrombin-stimulated activation of the clotting factors Factor X, Factor V, and prothrombin in contact-activated plasma at a concentration of 0.1 μM.2 Administration of bivalirudin (0.5-1.5 mg/kg, i.v.) reduces platelet deposition in a rat carotid endarterectomy model in a dose-dependent manner.3 Formulations containing bivalirudin have been used to prevent ischemic events during angioplasty for thrombus-containing lesions.4
1.Witting, J.I., Bourdon, P., Brezniak, D.V., et al.Thrombin-specific inhibition by and slow cleavage of hirulog-1Biochem J.283(Pt 3)737-743(1992) 2.Ofosu, F.A., Fenton, J.W., II, Maraganore, J.M., et al.Inhibition of the amplification reactions of blood coagulation by site-specific inhibitors of α-thrombinBiochem J.283(Pt 3)893-897(1992) 3.Hamelink, J.K., Tang, D.B., Barr, C.F., et al.Inhibition of platelet deposition by combined hirulog and aspirin in a rat carotid endarterectomy modelJ. Vasc. Surg.21(3)492-498(1995) 4.Shah, P.B., Ahmed, W.H., Ganz, P., et al.Bivalirudin compared with heparin during coronary angioplasty for thrombus-containing lesionsJ. Am. Coll. Cardiol.30(5)1264-1269(1997)