Tranexamic acid haemophilia drug. Person taking a tablet of the antifibrinolytic drug tranexamic acid. This drug is used to treat or prevent excessive blood loss from haemophilia, major trauma, postpartum bleeding, surgery, tooth removal, nosebleeds and heavy menstruation. Antifibrinolytic drugs prevent the breakdown of fibrin, a protein that is important in the coagulation of blood. They also inhibit the activation of plasminogen to plasmin, an enzyme that breaks down fibrin.