Andexanet alfa
⚡ Andexanet alfa (andexanet) is a specific reversal agent designed to neutralise the anticoagulant effects of both direct and indirect factor Xa inhibitors.
It is used in life-threatening bleeding associated with these drugs.
- First-in-class antidote for factor Xa inhibitors.
- Licensed in the UK (specialist hospital use only, usually after haematology/critical care discussion).
⚙️ Mode of Action
- Acts as a decoy protein for factor Xa inhibitors.
- Binds and reverses the activity of apixaban, rivaroxaban, and edoxaban.
- Restores thrombin generation and normal clotting.
🩺 Indications & Dosing
- Major or life-threatening bleeding associated with apixaban, rivaroxaban, or edoxaban.
- Dosing (trial regimens):
• Low dose: 400 mg IV bolus (30 mg/min) → then continuous infusion 4 mg/min for 120 min (total 480 mg).
• High dose: 800 mg IV bolus → then infusion 8 mg/min for 120 min (total 960 mg).
⚠️ Dose depends on the factor Xa inhibitor, timing, and dose last taken.
- Always consult local haematology/major haemorrhage protocol before use.
🔄 Interactions
- No direct drug–drug interactions listed, but see full BNF.
- Concurrent prothrombotic therapies (e.g. PCCs) may increase thrombosis risk.
⚠️ Cautions
- High risk of thromboembolic events after reversal (MI, stroke, DVT/PE).
- Restart anticoagulation as soon as clinically safe.
- Limited real-world evidence compared with PCCs → haematology input essential.
⛔ Contraindications
- See BNF for latest guidance.
- Generally avoided unless bleeding is uncontrolled and life-threatening.
⚠️ Side Effects
- Thrombosis (MI, stroke, PE, DVT).
- Infusion reactions: flushing, hot flushes.
- Back pain, chest pain, cough.
- Possible increased mortality compared with standard reversal (trial signal).
💡 Clinical Pearls
- 💉 Often stored only in tertiary centres / major trauma hospitals.
- 🧾 NICE and NHS England require strict criteria before release due to cost and risk.
- 🩸 Four-factor PCC (prothrombin complex concentrate) is sometimes used off-label where andexanet is not available.
- 👀 Always involve haematology early - this is not a “grab and give” drug.
📚 References
