From the Guidelines
Tranexamic acid (TXA) is a synthetic lysine analogue that exerts its mechanism of action by reversibly binding to plasminogen, thereby inhibiting its conversion to plasmin and subsequently reducing the breakdown of fibrin clots 1.
Key Mechanism of Action
- TXA is a competitive inhibitor of plasminogen, which is distributed throughout all tissues, with a plasma half-life of 120 minutes 1.
- By stabilizing fibrin clots, TXA effectively reduces bleeding in various clinical settings, including trauma, surgery, and menstrual disorders 1.
Dosage and Administration
- The recommended dose of TXA is a loading dose of 1 g infused over 10 minutes, followed by an intravenous infusion of 1 g over 8 hours 1.
- TXA should be administered as soon as possible, if feasible en route to the hospital, and within 3 hours after injury 1.
Clinical Settings
- TXA is effective in reducing bleeding in trauma patients who are bleeding or at risk of significant hemorrhage 1.
- TXA is also used in surgery and menstrual disorders to reduce bleeding 1.
From the FDA Drug Label
Tranexamic acid is a synthetic lysine amino acid derivative, which diminishes the dissolution of hemostatic fibrin by plasmin. In the presence of tranexamic acid, the lysine receptor binding sites of plasmin for fibrin are occupied, preventing binding to fibrin monomers, thus preserving and stabilizing fibrin’s matrix structure The antifibrinolytic effects of tranexamic acid are mediated by reversible interactions at multiple binding sites within plasminogen.
The mechanism of action of Tranexamic Acid (TXA) is as an antifibrinolytic agent, which works by:
- Occupying the lysine receptor binding sites of plasmin for fibrin, preventing binding to fibrin monomers
- Preserving and stabilizing fibrin's matrix structure
- Mediating reversible interactions at multiple binding sites within plasminogen 2
From the Research
Mechanism of Action of Tranexamic Acid (TXA)
- Tranexamic acid is a synthetic derivative of the amino acid lysine that exerts its antifibrinolytic effect through the reversible blockade of lysine binding sites on plasminogen molecules 3, 4, 5, 6.
- TXA acts by binding to plasminogen and blocking the interaction of plasmin(ogen) with fibrin, thereby preventing dissolution of the fibrin clot 3.
- The antifibrinolytic effect of TXA is achieved by competitively inhibiting plasminogen activation, thereby reducing conversion of plasminogen into plasmin, which ultimately prevents fibrinolysis and reduces hemorrhage 6.
Clinical Indications for TXA
- TXA is indicated in a variety of clinical settings, including postpartum hemorrhage, menorrhagia, trauma-associated hemorrhage, and surgical bleeding 3, 4, 5, 7.
- TXA has been shown to reduce perioperative blood loss and transfusion requirements in surgical procedures, including cardiac surgery, total hip and knee replacement, and prostatectomy 3, 4.
- TXA is also effective in reducing blood loss in gynaecological bleeding disorders, such as heavy menstrual bleeding, and in traumatic hyphaema, gastrointestinal bleeding, and hereditary angioneurotic oedema 3, 4, 5.