Bivalirudin

Angiomax / Angiox

Bivalirudin is a synthetic 20-amino-acid peptide anticoagulant and a direct thrombin inhibitor. It was designed based on hirudin, the natural anticoagulant that medicinal leeches use to keep blood flowing while they feed. Thrombin is the central clotting enzyme — it converts fibrinogen to fibrin and activates platelets — and bivalirudin blocks it directly and specifically. It does this bivalently: one end of the peptide binds thrombin's active (catalytic) site while the other binds a separate substrate-recognition region called exosite 1, clamping the enzyme at two points. Importantly, thrombin slowly cleaves the peptide at the active-site end, which partially restores thrombin function over time; this self-limiting behavior contributes to bivalirudin's short duration of action. Unlike heparin, bivalirudin does not require the cofactor antithrombin to work, and it can inhibit thrombin that is already bound within a clot — something heparin does poorly. It is given intravenously with a rapid onset and a short half-life (on the order of 25 minutes with normal kidney function), which makes its anticoagulant effect relatively easy to titrate and to let wear off. Its main use is as the procedural anticoagulant during percutaneous coronary intervention (PCI, such as coronary angioplasty and stenting), and it is an important option for anticoagulation in patients with heparin-induced thrombocytopenia (HIT), where heparin must be avoided. Bivalirudin is an approved prescription anticoagulant used in hospital and catheterization-lab settings. Like all anticoagulants its principal risk is bleeding, and because it is partly cleared by the kidneys, dosing is adjusted in kidney impairment. It is administered and monitored by clinicians — not a self-administered, research, or wellness peptide.