andexanet alfa at a glance
Medicine class
Specific factor Xa inhibitor reversal agent.
Licensed role
Urgent reversal of apixaban or rivaroxaban in adults with life-threatening or uncontrolled bleeding.
Administration
Reconstituted and given intravenously by hospital staff.
Important risk
Reversal exposes the patient to their underlying risk of blood clots; thrombotic events have also followed treatment.
What is andexanet alfa used for?
The selected UK product is licensed for emergency treatment in hospital.
Reversal of anticoagulation in adults taking apixaban when life-threatening or uncontrolled bleeding occurs.
Reversal of anticoagulation in adults taking rivaroxaban when life-threatening or uncontrolled bleeding occurs.
It is not licensed as a general antidote for every anticoagulant. Use for edoxaban or enoxaparin reversal is not recommended because data are insufficient.
How does andexanet alfa work?
Andexanet alfa is an inactive, modified form of human factor Xa. It acts as a decoy that binds apixaban or rivaroxaban, leaving less free anticoagulant available to block natural factor Xa. It also inhibits tissue factor pathway inhibitor, which can increase thrombin generation and may contribute to clotting risk.
andexanet alfa preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 200 mg
How to take andexanet alfa
Andexanet alfa is not taken by mouth and is restricted to hospital use. Trained staff reconstitute the powder and administer it through a vein using appropriate infusion equipment and a low-protein-binding filter.
Food and drink do not affect administration because treatment is intravenous.
Tell the team which anticoagulant was taken and when it was last taken, if known.
The clinical team decides when anticoagulation can safely be restarted after bleeding is controlled.
andexanet alfa side effects
Common or expected effects
- Fever.
- Serious thrombotic events reported as common adverse reactions include ischaemic stroke, heart attack, deep-vein thrombosis and pulmonary embolism.
Get urgent medical advice
- Sudden facial or arm weakness, speech difficulty, confusion or loss of vision may indicate a stroke.
- Chest pressure or pain, sweating, breathlessness or collapse may indicate a heart attack or cardiac arrest.
- Sudden breathlessness, chest pain, coughing blood, or a painful swollen limb may indicate a blood clot.
- Chills, breathing difficulty, reduced oxygen levels, marked blood-pressure changes, agitation or confusion during infusion require prompt assessment.
andexanet alfa in pregnancy
There are no adequate data from pregnant women, and reproductive studies are insufficient. The UK product information does not recommend andexanet alfa during pregnancy or for someone who could become pregnant and is not using contraception; an emergency specialist team must weigh the clinical circumstances.
andexanet alfa while breastfeeding
It is unknown whether andexanet alfa enters human milk, and risk to a breastfed child cannot be excluded. The UK product information says breastfeeding should be discontinued during treatment; discuss the circumstances with the treating specialist.
andexanet alfa interactions
Formal interaction studies have not been performed. Important practical concerns include:
Unfractionated heparin
Andexanet alfa can neutralise heparin's anticoagulant effect and cause heparin unresponsiveness, so use before procedures requiring heparinisation should be avoided.
Low-molecular-weight heparins
Their anticoagulant activity may be temporarily affected; andexanet alfa has not been evaluated or recommended as their antidote.
Prothrombin complex concentrates, activated concentrates, recombinant factor VIIa, fresh frozen plasma or whole blood
Combined use has limited safety evidence and should be avoided unless clinically essential.
Common questions about andexanet alfa
Answers are fully visible for fast scanning and source review.
Why is andexanet alfa given only in hospital?
It is an emergency intravenous treatment for severe bleeding that requires specialist selection, preparation and close monitoring for haemostasis, rebleeding, infusion reactions and blood clots.
Does andexanet alfa reverse every anticoagulant?
No. Its UK licence covers reversal of apixaban or rivaroxaban in adults with life-threatening or uncontrolled bleeding. It does not reverse anticoagulants that do not inhibit factor Xa.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.