A 68-year-old woman on warfarin for atrial fibrillation presents with severe posterior epistaxis uncontrolled by anterior and posterior nasal packing. Endoscopy confirms bleeding from the sphenopalatine artery. Which is the drug of choice for hemostasis in this scenario?

Explanation

## Systemic Hemostatic Therapy in Refractory Posterior Epistaxis **Key Point:** Intravenous tranexamic acid (TXA) is the first-line systemic hemostatic agent for severe, refractory epistaxis—particularly posterior bleeding in anticoagulated patients—because it inhibits fibrinolysis and stabilizes clot formation [cite:Dhingra's Diseases of ENT 8e Ch 8]. ### Mechanism of Action Tranexamic acid is a lysine analogue that competitively inhibits plasminogen activation and plasmin-mediated fibrin degradation. This preserves clot stability and promotes hemostasis without causing thrombosis. ### Clinical Indications for Systemic TXA 1. **Refractory epistaxis** despite topical measures and packing 2. **Anticoagulation-related bleeding** (warfarin, DOACs, heparin) 3. **Coagulopathy or thrombocytopenia** with active epistaxis 4. **Posterior epistaxis** where local measures have failed 5. **Recurrent epistaxis** in patients with hereditary hemorrhagic telangiectasia (HHT) ### Dosing and Administration - **Loading dose:** 10–15 mg/kg IV over 10 minutes (typically 1 g in 100 mL normal saline) - **Maintenance:** 1 g IV every 6–8 hours for 2–3 days, or until hemostasis achieved - **Oral alternative:** 1.5 g three times daily (if IV access unavailable) ### Efficacy and Evidence - **Success rate:** 70–85% in refractory epistaxis when combined with other measures - **Onset:** Hemostatic effect within 15–30 minutes - **Safety:** Well-tolerated; contraindicated only in active thrombosis or severe renal impairment (Cr >2.5 mg/dL) ### Comparison of Hemostatic Agents in Posterior Epistaxis | Agent | Route | Mechanism | Role in Posterior Epistaxis | Limitation | | --- | --- | --- | --- | --- | | **Tranexamic acid** | IV/oral | Fibrinolysis inhibition | **First-line systemic agent** | Requires IV access; contraindicated in thrombosis | | Topical thrombin | Topical | Thrombin-fibrinogen interaction | Adjunct for oozing; poor efficacy in brisk bleeding | Cannot reach posterior sphenopalatine artery reliably | | Adrenaline (1:1000) | Topical | Vasoconstriction | Anterior epistaxis only | Ineffective for posterior bleeding; systemic absorption risk | | Calcium alginate gauze | Topical | Mechanical hemostasis + ion exchange | Packing adjunct only | Does not address underlying coagulopathy | **High-Yield:** TXA is superior to topical agents alone in posterior epistaxis because it addresses the underlying fibrinolytic state systemically, whereas topical hemostatics (thrombin, adrenaline) cannot reliably reach the sphenopalatine artery and are ineffective in the presence of active anticoagulation. **Mnemonic:** **TRAM** = **TRAnexamic acid for Massive/refractory bleeding** — think "tram" as a systemic vehicle carrying hemostatic effect throughout the body. **Clinical Pearl:** In anticoagulated patients with epistaxis, always consider **reversing anticoagulation** (warfarin reversal with vitamin K + FFP/PCC; DOAC reversal with specific antidotes) *in addition to* TXA, as this addresses the root cause. **Warning:** Do not confuse topical thrombin (bovine-derived) with systemic TXA. Topical thrombin has poor penetration in posterior epistaxis and is primarily useful for oozing from small anterior vessels or surgical sites.