Fibrinolytiques

Fibrinolytiques are a class of enzymes and medications that play a crucial role in breaking down fibrin, a protein involved in blood clotting. This process is known as fibrinolysis, a natural mechanism that prevents excessive clot formation and maintains vascular patency. Fibrinolytic agents are used therapeutically to dissolve abnormal blood clots, particularly in conditions such as deep vein thrombosis, pulmonary embolism, and acute myocardial infarction.

The primary endogenous fibrinolytic enzyme is plasmin, which is generated from its precursor, plasminogen, through the action of activators like tissue plasminogen activator (tPA) and urokinase. Exogenous fibrinolytics, such as streptokinase, alteplase (recombinant tPA), and tenecteplase, are derived from natural sources or produced synthetically to mimic the body’s fibrinolytic pathways.

Fibrinolytic therapy is essential in acute coronary syndromes, where rapid clot dissolution can restore blood flow to ischemic myocardium, reducing tissue damage. However, these agents carry risks, including bleeding complications, which necessitate careful patient selection and monitoring. Contraindications include recent surgery, active bleeding, and severe hypertension, as these increase the likelihood of hemorrhage.

Common side effects include bleeding at injection sites, gastrointestinal bleeding, and intracranial hemorrhage in rare cases. Monitoring parameters typically include coagulation tests, such as prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen levels. Anticoagulants and antiplatelet agents may be used in conjunction with fibrinolytics to enhance efficacy while managing bleeding risks.

Resistance to fibrinolytic therapy can occur due to impaired plasminogen activation or elevated levels of fibrinolytic inhibitors, such as plasminogen activator inhibitor-1 (PAI-1). Research continues to explore novel fibrinolytic agents and adjunctive therapies to improve outcomes while minimizing complications.