USMLE

Factor Xa Inhibitors (Apixaban, Rivaroxaban, Edoxaban)

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Heme Pharm
  1. Warfarin
  2. Heparin
  3. Low Molecular Weight Heparins (LMWH)
  4. Direct Thrombin Inhibitors (Argatroban, Dabigatran, Bivalirudin)
  5. Thrombolytics (tPA, Streptokinase, Urokinase)
  6. ADP Receptor Inhibitors
  7. PDE3 Inhibitors (Cilostazol, Dipyridamole)
  8. Glycoprotein IIb/IIIa Inhibitors
  9. Factor Xa Inhibitors (Apixaban, Rivaroxaban, Edoxaban)

Summary

Factor Xa inhibitors are orally-taken anticoagulant drugs that end with the common suffix, -xaban. Drug names of this group include apixaban, edoxaban, and rivaroxaban.  These drugs work by inhibiting factor Xa, which is the common link between the extrinsic and intrinsic coagulation pathways in forming blood clots. The inhibition of factor Xa  inhibits thrombin production, which inhibits blood clotting. Factor Xa inhibitors are used clinically for patients with deep venous thrombosis, venous thromboembolisms, or patients at risk of clotting due to nonvalvular atrial fibrillation.

Key Points

  • Factor Xa Inhibitors
    • Drug names
      • -xaban drugs: Apixaban, Rivaroxaban, Edoxaban
    • Mechanism
      • Competitive inhibitors of Factor Xa (Factor IIa)
        • Bind to Factor Xa, inactivating it and preventing thrombin formation (secondary hemostasis)
        • Blocks the common pathway of the coagulation cascade
      • Administered orally
        • Long half-life; do not require routine lab monitoring
        • Convenience has made the use of these drugs very common
    • Clinical Use
      • Nonvalvular atrial fibrillation
      • Venous thromboembolism (VTE) prophylaxis
        • After PE or DVT
        • After orthopedic surgery (hip, total knee)
    • Laboratory Findings
      • No change in thrombin time (TT)
        • No problems in thrombin or fibrinogen, which happen after Xa in coagulation cascade
      • Elevated PT and PTT
        • Should make sense in light of Xa inhibition
    • Adverse Effects
      • Bleeding
        • Obvious side effect seen in all anticoagulants
    • Reversal
      • Andexanet alfa (recombinant Factor Xa)
        • Very new agent (FDA approved in 2018)