💊 Tranexamic Acid

Tranexamic acid is an antifibrinolytic agent that inhibits fibrinolysis, thereby promoting clot stability. It is a synthetic derivative of the amino acid lysine.

Tranexamic acid competitively inhibits the activation of plasminogen to plasmin. Plasmin is an enzyme responsible for breaking down fibrin clots (fibrinolysis). By preventing plasmin formation, tranexamic acid stabilises existing clots and reduces bleeding.

Tranexamic acid is widely used to reduce bleeding in various clinical settings, including menorrhagia, post-partum haemorrhage, and epistaxis. It is also indicated for the prevention and treatment of haemorrhage in patients with haemophilia undergoing dental procedures or surgery. Furthermore, it is used in trauma to reduce mortality from haemorrhage and in surgical procedures with high blood loss.

Absolute contraindications include active intravascular clotting (e.g., DVT, PE, cerebral thrombosis) and a history of convulsions. It is also contraindicated in patients with severe renal impairment due to accumulation. Caution is advised in patients with a history of thromboembolic disease, haematuria (risk of ureteric obstruction), or concurrent use of oestrogen-containing contraceptives.

Common adverse effects include gastrointestinal disturbances such as nausea, vomiting, and diarrhoea. Visual disturbances, including colour vision impairment, can occur. Less common but serious adverse effects include thromboembolic events (e.g., DVT, PE, MI, stroke), particularly in predisposed individuals, and convulsions. Allergic reactions are rare.

No routine specific blood monitoring is typically required for tranexamic acid. However, renal function should be assessed, especially in patients with pre-existing renal impairment, as dose adjustments may be necessary. Patients should be monitored for signs of thromboembolic events or visual disturbances.

Always check for active thromboembolic disease, severe renal impairment, and a history of convulsions. Ensure the correct route of administration (oral or IV). Counsel patients on potential side effects, particularly gastrointestinal upset and the importance of reporting any visual changes or signs of thrombosis. Be aware of interactions with hormonal contraceptives.

Tranexamic acid is a crucial agent for managing and preventing bleeding, particularly in obstetric emergencies and trauma. Remember its antifibrinolytic mechanism and its role in stabilising clots. It is important to differentiate it from procoagulant agents. The risk of thrombosis, though low, is a key consideration, especially in patients with pre-existing risk factors.

SBAs often test the indications for tranexamic acid, particularly in acute bleeding scenarios like trauma or post-partum haemorrhage. Questions may also focus on its mechanism of action as an antifibrinolytic. Recognising contraindications, especially active thrombosis or severe renal impairment, is a common theme.