Which medications in the drug class Factor Xa Inhibitors are used in the treatment of Protein S Deficiency?

Updated: Jan 03, 2021
  • Author: Mohammad Muhsin Chisti, MD, FACP; Chief Editor: Perumal Thiagarajan, MD  more...
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Answer

Factor Xa Inhibitors

These agents bind to factor Xa and prevent it from cleaving prothrombin to thrombin.

Rivaroxaban (Xarelto)

Orally administered factor Xa inhibitor that inhibits platelet activation by selectively blocking the active site of factor Xa without requiring a cofactor (eg, antithrombin III) for activity. 

Its anticoagulant action develops within 2-4 hours of ingestion and lasts for approximately 24 hours. It should be used if the creatinine clearance is < 15mL/min. 

Rivaroxaban does not require monitoring of PT and aPTT. However, its presence can be tested by the prothrombin time (PT) or anti–factor Xa activity.

Apixaban (Eliquis)

Factor Xa inhibitor that inhibits platelet activation by selectively and reversibly blocking the active site of factor Xa without requiring a cofactor (eg, antithrombin III) for activity. It is metabolized in the liver via CYP3A4/5.

Used in patients with atrial fibrillation to prevent venous thromboembolism and stroke.

PT, aPTT and INR are prolonged but, routinely no monitoring is required. Anti-Xa assay can be used to rely upon if testing is necessary.

Edoxaban (Savaysa)

Orally active, with a half life of 6-11 hours. Undergoes hydrolysis, conjugation and oxidation by CYP3A4. Inhibits free Xa, prothrombinase activity and thrombin-induced platelet aggregation without requiring routine monitoring. 

Fondaparinux (Arixtra)

This compound is a novel pentasaccharide capable of inhibiting factor Xa via the action of antithrombin (AT) but devoid of anti-factor IIa (thrombin) activity. Interestingly, this compound does not appear to cross-react with HIT antibodies.

Approved for use in hip fracture surgery, knee replacement surgery, and hip replacement surgery. Only FDA-approved anticoagulant drug for hip fracture surgery. Also used and approved for extended prophylactic dosing for 21 d following hip fracture surgery.


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