What is the mechanism of action of RIVAROXABAN?

Correct answer: A. Direct inhibition of factor Xa

• A. CORRECT. RIVAROXABAN is a direct oral anticoagulant (DOAC) that binds and directly inhibits FACTOR Xa, blocking the conversion of prothrombin to thrombin at the convergence point of the intrinsic and extrinsic pathways. Apixaban and edoxaban share this mechanism — the '-xaban' suffix is a reliable cue.
• B. Irreversible platelet COX inhibition is the mechanism of ASPIRIN — an antiplatelet agent, not an anticoagulant.
• C. Inhibition of VITAMIN K EPOXIDE REDUCTASE is the mechanism of WARFARIN, which depletes factors II, VII, IX and X and is monitored by INR.
• D. Direct THROMBIN inhibition is the mechanism of DABIGATRAN (and of argatroban and bivalirudin).

Note: Practical dental management: DOACs do NOT require INR monitoring, and current guidance is NOT to interrupt them for routine extractions or minor oral surgery. Schedule treatment as late as possible in the dosing interval, use local haemostatic measures (sutures, oxidised cellulose, tranexamic acid mouthwash), and consult the physician before any extensive surgery. Reversal: idarucizumab for dabigatran, andexanet alfa for the factor Xa inhibitors.