andexanet alfa
Brand: Andexxa
Prototype Drug
Drug Class: anticoagulant reversal agent
Drug Family: reversal agent
Subclass: recombinant modified factor Xa (decoy)
Organ Systems: cardiovascularhematology-oncology
Mechanism of Action
Recombinant modified factor Xa lacking catalytic activity acting as decoy receptor; competitively binds and sequesters direct Xa inhibitors (rivaroxaban, apixaban); also reverses LMWH/fondaparinux partially.
factor Xa inhibitors (rivaroxaban, apixaban, edoxaban)
Indications
- reversal of rivaroxaban or apixaban for life-threatening bleeding
Contraindications
- no absolute contraindications; not approved for dabigatran reversal
Adverse Effects
Common
- hypersensitivity reactions
Serious
- thromboembolic events (rebound prothrombotic state)
- arteriolar thrombosis
Pharmacokinetics (ADME)
| Absorption | IV only |
| Distribution | intravascular |
| Metabolism | proteolytic degradation |
| Excretion | proteolysis |
| Half-life | ~1 hour |
| Onset | immediate IV |
| Peak | immediate |
| Duration | 2-4 hours |
| Protein Binding | <0% |
| Vd | low |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| rivaroxaban/apixaban | specific reversal — beneficial | beneficial |
Nursing Considerations
- ANNEXA-4 study: effective reversal of anti-Xa activity within 2-5 minutes
- Two dosing regimens based on which drug and when last dose taken
- Thrombosis risk: anti-Xa reversal may lead to rebound pro-thrombotic state; restart anticoagulation as soon as clinically safe
- Very expensive (>$25,000 per dose); 4-factor PCC is an alternative
Clinical Pearls
- Decoy mechanism: acts as competitive 'trap' for Xa inhibitors; does not carry catalytic activity so does not cause thrombosis directly
- ANNEXA-4: hemostatic efficacy in 82% for apixaban, 79% for rivaroxaban — 30-day thrombosis rate elevated vs historical
Safety Profile
Pregnancy insufficient-data
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Guideline Update pending
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.