It is a novel recombinant modified protein that is parallel to local
factor Xa. It binds to
factor Xa inhibitors in the blood thus avoiding them from inhibiting the action of the native
factor Xa.
Measuring oral direct inhibitors of thrombin and
factor Xa: a recommendation from the Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis.
Rivaroxaban is an orally administered, selective, reversible, direct inhibitor of activated factor X (
factor Xa), and is currently indicated for prophylaxis of venous thromboembolism (VTE) in adults after hip or knee replacement surgery.
The limitations of this study include a small patient population, uncontrolled design (use of 4F-PCC was at the discretion of the provider), and higher rates of spontaneous ICH vs traumatic ICH in the
factor Xa inhibitor group compared to the VKA group.
Fortunately, since 2015, a specific reversal agent for dabigatran, idarucizumab, has been FDA-approved, with two other agents (andexanet-a and ciraparantag) have been fast-tracked through the FDA for potential approval for the reversal of the
factor Xa inhibitors.
Neither heparin nor
factor Xa inhibitor rivaroxaban significantly increased free hemoglobin in the brain (Figure 2).
Weinz, "In vitro metabolism of rivaroxaban, an oral, direct
factor xa inhibitor, in liver microsomes and hepatocytes of rats, dogs, and humans," Drug Metabolism and Disposition, vol.
In a phase III trial, andexanet alfa was shown to reverse the effects of two
factor Xa inhibitors, apixaban and rivaroxaban.
The molecular weight affects the specificity that each LMWH has to binding
factor Xa or II, with smaller molecular weights selectively targeting
factor Xa compared with factor II.
No recommendation was made for apixaban (Eliquis) in patients with severe or end-stage renal impairment, because of a lack of published data, although a recent secondary analysis of the ARISTOTLE (Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) trial suggests the direct
factor Xa inhibitor provides the greatest reduction in major bleeding in patients with impaired renal function compared with warfarin (Eur.
The guidelines advise evaluating renal function prior to initiating any of the direct thrombin or
factor Xa inhibitors, and to reevaluate at least annually and when clinically indicated.