Oral factor Xa inhibitor is:-
**Core Concept**
Factor Xa inhibitors are a class of anticoagulant medications that work by blocking the activity of factor Xa, a key enzyme in the coagulation cascade. By inhibiting factor Xa, these medications reduce the formation of thrombin and subsequent clot formation.
**Why the Correct Answer is Right**
Apixaban is an oral factor Xa inhibitor that selectively binds to and inhibits factor Xa. This results in a decrease in the levels of thrombin and subsequent clot formation. Apixaban is a direct oral anticoagulant (DOAC) that has been shown to be effective in preventing stroke and systemic embolism in patients with non-valvular atrial fibrillation.
**Why Each Wrong Option is Incorrect**
**Option A:** Rivaroxaban is also an oral factor Xa inhibitor, but it is not the correct answer in this case.
**Option B:** Dabigatran is a direct oral anticoagulant that inhibits thrombin, not factor Xa.
**Option C:** Warfarin is a vitamin K antagonist that inhibits the production of vitamin K-dependent clotting factors, including factor Xa, but it is not an oral factor Xa inhibitor.
**Clinical Pearl / High-Yield Fact**
When choosing an anticoagulant for a patient with non-valvular atrial fibrillation, consider the patient's renal function, as factor Xa inhibitors like apixaban are primarily excreted by the kidneys.
**Correct Answer:** B. Dabigatran is a direct oral anticoagulant that inhibits thrombin, not factor Xa.