rivaroxaban
Summary
Rivaroxaban is an oral direct factor Xa inhibitor used for anticoagulation, including prevention/treatment of DVT/PE, stroke prevention in nonvalvular atrial fibrillation, and VTE prophylaxis after orthopedic surgery. Unlike warfarin, it has a rapid onset, fixed dosing, and does not require routine INR monitoring.
Detail
Rivaroxaban belongs to the class of direct oral anticoagulants (DOACs), specifically a direct factor Xa inhibitor. It works by directly and selectively binding to the active site of factor Xa, inhibiting both free and clot-bound factor Xa, thereby preventing the conversion of prothrombin (factor II) to thrombin (factor IIa) and subsequent fibrin clot formation. This differs from warfarin, which inhibits vitamin K epoxide reductase and affects synthesis of factors II, VII, IX, X, and proteins C and S.
Clinical indications include: prevention of stroke and systemic embolism in nonvalvular atrial fibrillation, treatment and secondary prevention of DVT/PE, VTE prophylaxis after hip/knee replacement surgery, and reduction of risk in patients with coronary or peripheral artery disease (in combination with aspirin).
Pharmacokinetics: rapid onset of action (peak effect within 2-4 hours), primarily metabolized by CYP3A4/CYP2J2 and eliminated via both renal (33%) and fecal/biliary routes, requiring dose adjustment in renal impairment. Unlike warfarin, no routine coagulation monitoring is needed, though anti-Xa assays can measure drug levels if necessary.
Key advantages over warfarin: predictable pharmacokinetics, fewer drug-food interactions, no need for bridging therapy in most cases, and lower risk of intracranial hemorrhage. Disadvantages: higher cost, limited reversal options historically (though andexanet alfa is now available as a specific reversal agent), and contraindication in patients with mechanical heart valves or moderate-severe mitral stenosis (where warfarin remains preferred).
Major adverse effect is bleeding, particularly GI bleeding. Contraindicated in active pathological bleeding and severe hepatic impairment. Must be used cautiously with other CYP3A4/P-glycoprotein inhibitors or inducers (e.g., ketoconazole, rifampin) due to altered drug levels. For USMLE purposes, know rivaroxaban as a factor Xa inhibitor (along with apixaban, edoxaban) versus dabigatran (direct thrombin/factor IIa inhibitor) in the DOAC class.
Sources
- First Aid for the USMLE Step 1
- Katzung's Basic and Clinical Pharmacology
- Goodman & Gilman's The Pharmacological Basis of Therapeutics
- UpToDate: Direct oral anticoagulants (DOACs)
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.