antifibrinolytics

Antifibrinolytics are medications that inhibit fibrinolysis, the breakdown of blood clots. By blocking the activation of plasminogen to plasmin or by directly inhibiting plasmin, these drugs help stabilize clots and reduce bleeding. They are used as adjuncts to hemostasis in various settings, including surgery and conditions associated with excessive bleeding.

The two main clinically used classes are lysine analogs and serine protease inhibitors. The lysine analogs, tranexamic acid and epsilon-aminocaproic acid (EACA, aminocaproic acid), competitively bind to plasminogen and plasmin, decreasing fibrinolysis. Aprotinin, a broad-spectrum serine protease inhibitor, was historically used to reduce bleeding in high-risk surgeries but has seen restricted use due to safety concerns.

Common indications include reduction of perioperative blood loss in procedures such as orthopedic, cardiovascular, and obstetric surgeries; control of mucosal or spontaneous bleeding in certain bleeding disorders; and prevention or treatment of heavy menstrual bleeding. They can be given orally or intravenously, with dosing tailored to the indication, patient age, and renal function.

Adverse effects vary by agent but can include thromboembolic events, nausea, diarrhea, headache, and hypotension with intravenous administration. High-dose tranexamic acid has been associated with seizures in susceptible individuals. Contraindications include active intravascular clotting, history of thromboembolism, significant renal impairment without dose adjustment, and known hypersensitivity. Antifibrinolytics are generally used as adjuncts to control bleeding rather than as primary therapies.