Factor Xa Inhibitors

How to Cite This Chapter: Douketis J, Undas A, Zawilska K. Factor Xa Inhibitors. McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. https://empendium.com/mcmtextbook/chapter/B31.II.2.34.2. Accessed May 22, 2024.
Last Updated: June 11, 2021
Last Reviewed: June 11, 2021
Chapter Information

1. Mechanism of action: Fondaparinux (subcutaneous or IV) is a synthetic pentasaccharide that binds only to antithrombin; apixaban (oral), edoxaban (oral), rivaroxaban (oral), and betrixaban (oral) cause factor Xa inhibition that is not mediated by antithrombin.

2. Monitoring of the anticoagulant effect is not necessary. However, within 2 to 4 hours of the administration of rivaroxaban, a prolonged prothrombin time (international normalized ratio [INR]) typically occurs (the effect is less pronounced after the administration of apixaban). Rivaroxaban, apixaban, and edoxaban have little or no effect on the activated partial thromboplastin time (aPTT) and thrombin time. In patients planned for urgent invasive procedures associated with a high risk of bleeding, the prothrombin time (PT) and aPTT are not reliable tests to measure the anticoagulant effect of apixaban, edoxaban, and rivaroxaban. More reliable measures of the anticoagulant effects of rivaroxaban, apixaban, and edoxaban require the use of anti–factor Xa assays specific to these agents.

3. Contraindications are the same as with heparins and additionally include pregnancy and breastfeeding; do not use these agents in patients with creatinine clearance <15 mL/min, patients with severe liver failure, or in combination with other anticoagulants, dual antiplatelet therapy, thrombolytic agents, and drugs that can potentiate or impede the anticoagulant effect (eg, azole antifungal agents, and HIV protease inhibitors). Blood levels of rivaroxaban increase in patients receiving concomitant clarithromycin, erythromycin, cyclosporine (INN ciclosporin), tacrolimus, or fluconazole. Rifampin (INN rifampicin), phenobarbital, carbamazepine, phenytoin, and hypericum (St John’s wort) reduce the efficacy of rivaroxaban and apixaban.

4. Discontinuation of treatment before surgical procedures: see Perioperative Direct Oral Anticoagulant (DOAC) Management.

5. Complications: Mainly bleeding (in contrast to heparins, factor Xa inhibitors are not known to cause heparin-induced thrombocytopenia), allergic reactions. Andexanet alfa is available is some countries to neutralize the anticoagulant effect but is expensive and not widely available. The anticoagulant effect of oral factor Xa inhibitors may be neutralized by a 4-factor prothrombin complex concentrate (PCC) 25 IU/kg (the dose may be repeated twice). The role of other prohemostatic agents, which include tranexamic acid, cryoprecipitate, and recombinant factor VII, in bleeding management is uncertain but can be considered in cases of bleeding that is refractory to administration of reversal agents. In addition, there is uncertainty about the potential prothrombotic effects of all prohemostatic agents in this clinical setting.

We would love to hear from you

Comments, mistakes, suggestions?

We use cookies to ensure you get the best browsing experience on our website. Refer to our Cookies Information and Privacy Policy for more details.