Direct oral anticoagulants rivaroxaban, edoxaban, and apixaban are direct factor Xa inhibitors.

• A. True
• B. False
• C. Not applicable
• D. Some are direct factor Xa inhibitors only

Answer: (A)

This asks about how these oral anticoagulants work. Rivaroxaban, apixaban, and edoxaban act directly on factor Xa, binding to Xa and inhibiting its enzymatic activity. By stopping Xa, they prevent the conversion of prothrombin to thrombin, which reduces thrombin generation and clot formation. They do this directly, without needing antithrombin as a mediator, distinguishing them from indirect Xa inhibitors like fondaparinux, which work through antithrombin. It’s also helpful to note that dabigatran is a direct thrombin (factor IIa) inhibitor, not a Xa inhibitor, which is why these three are correctly described as direct factor Xa inhibitors.