Bivalirudin is an anticoagulant medication used to prevent blood clots during certain medical procedures, particularly in patients undergoing percutaneous coronary interventions (PCI). It works by directly inhibiting thrombin, an enzyme crucial for blood clot formation, thereby reducing the risk of clot-related complications. This medication is typically administered intravenously and is favored for its predictable effects and shorter half-life compared to other anticoagulants. Bivalirudin is often used in patients with a history of heparin-induced thrombocytopenia, a condition that makes traditional anticoagulants less effective or safe.