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# Tranexamic Acid ## Overview Tranexamic acid is a synthetic derivative of the amino acid lysine. It acts as an antifibrinolytic agent by competitively inhibiting the activation of plasminogen to plasmin. Plasmin is a crucial enzyme in fibrinolysis, the breakdown of blood clots. By reducing plasmin activity, tranexamic acid stabilizes clots and prevents excessive bleeding. ## Primary Indications * Hemorrhagic stroke (intracerebral hemorrhage) * Menorrhagia (heavy menstrual bleeding) * Hereditary angioedema (prophylaxis and treatment of acute swelling episodes) * Bleeding associated with excessive fibrinolysis (e.g., post-surgical, trauma, certain hematologic disorders) * Preventive use in certain surgical procedures to reduce blood loss (e.g., cardiac, orthopedic, obstetric) ## Adult Dosing * **Hemorrhagic Stroke:** Typically 1 gram IV every 6 to 8 hours. Maximum dose often established by local protocol, but commonly not exceeding 4-6 grams per day. * **Menorrhagia:** Oral: 1 gram orally three times daily for up to 4 days during menstruation. Maximum daily dose is 3 grams. * **Hereditary Angioedema:** * *Prophylaxis:* Oral: 1000-1500 mg orally two to three times daily. * *Acute Episodes:* Oral: 1000-1500 mg orally every 6 to 8 hours. IV dosing may be used in severe cases, often 500-1000 mg IV every 6 to 8 hours, but specific IV protocols vary. * **Perioperative:** IV: 1 gram IV at induction of anesthesia, followed by 1 gram IV three to four hours later, or as a continuous infusion (e.g., 100 mg/hour) depending on the surgical procedure and local protocol. Maximum dose often 4-6 grams per day. * **Other Bleeding:** IV: Dosing varies significantly based on the clinical scenario and degree of fibrinolysis. Common initial doses range from 500 mg to 1 gram IV bolus, followed by infusions or repeated boluses. Always guided by clinical assessment and local protocols. ## Pediatric Dosing * Dosing in children is not well-established and should be based on body weight and clinical judgment, often with reference to adult dosing or specialized pediatric guidelines. * For menorrhagia, oral doses may range from 20-25 mg/kg/day divided into 3-4 doses, not to exceed adult doses. * IV dosing for pediatric hemorrhage is highly individualized. ## Dose Adjustments * **Renal Impairment:** Dose reduction is necessary. * Creatinine clearance (CrCl) 50-80 mL/min: Reduce dose by 50%. * CrCl 10-50 mL/min: Reduce dose by 75% or administer every other day. * CrCl <10 mL/min: Administer every third day or reduce dose by 75%. * Dosing in mL/min may need to be calculated and adjusted accordingly. * **Hepatic Impairment:** No dose adjustment is typically required as it is not metabolized by the liver. However, caution is advised in severe hepatic dysfunction due to potential alterations in coagulation. ## Contraindications * Active intravascular clotting (e.g., disseminated intravascular coagulation without co-administration of heparin) * Hypersensitivity to tranexamic acid * Acquired defects in color vision * Subarachnoid hemorrhage (risk of vasospasm and cerebral ischemia) ## Adverse Effects * **Common:** Nausea, vomiting, diarrhea, abdominal pain. * **Less Common:** Dizziness, headache, allergic reactions. * **Serious:** * Thromboembolic events (deep vein thrombosis, pulmonary embolism, cerebral venous thrombosis, myocardial infarction, arterial thrombosis) - risk is increased in patients with risk factors for thrombosis or when used concomitantly with combined oral contraceptives. * Hypotension (especially with rapid IV infusion). * Seizures (associated with high IV doses, particularly in patients with a history of seizures or those receiving certain neurosurgical procedures). * Visual disturbances (rare, typically with prolonged high-dose therapy). ## Key Drug Interactions * **Hormonal contraceptives (oral, transdermal, vaginal):** Increased risk of venous thromboembolism. * **Factor VIIa (recombinant):** Increased risk of thrombosis. * **Antifibrinolytics (e.g., aminocaproic acid):** Concurrent use is generally avoided due to additive prothrombotic risk. * **Oral contraceptives:** Higher risk of thromboembolic events. ## Monitoring * **Clinical efficacy:** Monitor for reduction in bleeding or stabilization of clot. * **Adverse effects:** Watch for signs/symptoms of thromboembolic events, GI distress, visual changes, and neurological changes (seizures). * **Renal function:** Essential for dose adjustments. * **Hematologic parameters:** Coagulation studies (PT, PTT, D-dimer) may be helpful in assessing fibrinolytic activity but are not always routinely monitored. * **Visual acuity and color vision:** Recommended for patients on long-term, high-dose therapy. ## Clinical Pearls * Rapid IV infusion can cause hypotension; administer slowly. * While tranexamic acid reduces bleeding, it does not address the underlying cause of hemorrhage. * The risk of thromboembolic events is a significant concern, especially in patients with predisposing factors or those using hormonal contraceptives. Carefully weigh risks versus benefits. * Oral administration is 3-5 times less bioavailable than IV. * Dosing for pediatric patients requires careful consideration and often expert consultation. *** *This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and your healthcare provider for any health concerns or before making any treatment decisions.*