Generic Name

Tranexamic acid

Mechanism

Tranexamic acid is a synthetic antifibrinolytic that reversibly binds to lysine‑binding sites on plasminogen molecules, blocking their conversion to active plasmin. By inhibiting plasmin formation, it prevents fibrin clot degradation, thereby stabilizing hemostasis and reducing bleeding.
• *Key Points:*
• Competitive plasminogen inhibitor.
• Allosteric inhibition of fibrinolysis.
• Useful in conditions where excessive fibrinolysis is a primary contributor to hemorrhage.

Pharmacokinetics

Tranexamic acid exhibits predictable absorption and distribution characteristics:
• Absorption: Rapid oral uptake; peak plasma concentrations achieved within 30‑60 min.
• Distribution: Widely distributed, with a volume of distribution ~1.4 L/kg.
• Metabolism: Minimal hepatic metabolism; largely unchanged.
• Elimination: Primarily renal excretion; half‑life ~2–3 h in healthy adults.
• Renal impairment: Dose reduction recommended; in severe renal failure, monitor levels to avoid accumulation.

Indications

Tranexamic acid is indicated for:
• Reducing perioperative bleeding in cardiac, orthopedic, and general surgical procedures.
• Treating heavy menstrual bleeding (menorrhagia).
• Managing traumatic hemorrhage and combat casualties.
• Arresting localized bleeding from dental procedures and gastrointestinal bleeding (off‑label, under specialist guidance).
• Off‑label use in acute ischemic stroke to limit peri‑bleed expansion when coupled with thrombolytics.

Contraindications

• Absolute Contraindication: Known hypersensitivity to tranexamic acid or any excipient.
• Relative Contraindication/Warning:
• Active thromboembolic disease (deep venous thrombosis, pulmonary emboli).
• Severe renal impairment (creatinine clearance <30 mL/min).
• History of intracranial hemorrhage or stroke.
• Use caution in patients undergoing antifibrinolytic therapy (e.g., bivalirudin) due to synergistic effects.

Dosing

• Bolus Dose (IV): 10‑15 mg/kg over 15 min to initiate hemostasis.
• Maintenance Infusion (IV): 1 mg/kg/h for 6–24 h, titrated based on surgical bleeding.
• Oral Dose (Menorrhagia): 1 g twice daily for 3–4 weeks, or 1 g four times daily for severe bleeding.
• Trauma/Combat (IV): 1 g over 10 min, repeat every 12 h for 48 h.
• Intermediate‑volume oral (e.g., 550 mg tablets): 1 g q6h with food, monitor gastrointestinal tolerability.

Note: End of infusion administration requires flushing the line with saline to avoid catheter blockage.

Adverse Effects

• Common: nausea, vomiting, abdominal discomfort, dizziness.
• Serious:
• Potential thrombotic events (deep vein thrombosis, pulmonary embolism).
• Ocular toxicity (ocular hemorrhage, retinal vascular occlusion in rare cases).
• Seizures in patients with renal failure or overdose.
• Neurologic side effects in severe systemic inflammation.

Monitoring

• Renal Function: Serum creatinine, BUN, and estimated glomerular filtration rate (eGFR) before initiation and periodically during therapy.
• Coagulation Profile: PT, aPTT, fibrinogen levels to ensure hemostasis is maintained.
• Bleeding Assessment: Hemoglobin/hematocrit trends, net fluid balance, and clinically observed hemorrhage.
• Adverse Events: Regular evaluation for signs of thrombosis (leg swelling, pain) and neurological status.

Clinical Pearls

1. Start with a loading dose: Rapidly stabilizes fibrin clots in trauma; ideal for pre‑hospital settings.
2. Use renal‑adjusted dosing: Prevents accumulation; employ 5 mg/kg/h in creatinine clearance 20‑30 mL/min.
3. Avoid in acute ischemic stroke: When given with tPA, risk of hemorrhagic transformation increases; use only in selected clinical trials.
4. Oral tablets may cause mild GI upset but are well tolerated in menstrual bleeding if taken with food.
5. Combine with antifibrinolytic agents cautiously: Dual therapy may amplify thrombotic risk and should be reserved for cases of massive hemorrhage where standard dosing fails.
6. Document bleeding parameters: Accurate pre‑ and post‑infusion records help differentiate drug efficacy from natural hemostatic recovery.

These high‑yield insights assist medical students and clinicians in prescribing Tranexamic acid safely and effectively across diverse bleeding scenarios.