Rivaroxaban is a direct oral anticoagulant (DOAC). Which feature of its pharmacokinetics distinguishes it from apixaban with respect to renal elimination?
- A Rivaroxaban is primarily eliminated by biliary excretion; apixaban is entirely renally cleared
- B Approximately 35% of rivaroxaban is excreted unchanged by the kidneys (renal-dependent clearance); apixaban has only ~27% renal elimination, making rivaroxaban more dependent on renal function for dose adjustment ✓
- C Both are >90% renally eliminated and require similar dose reduction in renal failure
- D Rivaroxaban is fully reversed by idarucizumab; apixaban has no specific antidote
Correct answer: B. Approximately 35% of rivaroxaban is excreted unchanged by the kidneys (renal-dependent clearance); apixaban has only ~27% renal elimination, making rivaroxaban more dependent on renal function for dose adjustment
Explanation
Rivaroxaban has approximately 35% unchanged renal excretion plus additional hepatic CYP3A4 metabolism; apixaban has approximately 27% renal elimination, making it slightly less renally dependent. By contrast, dabigatran has approximately 80% renal elimination, requiring the most careful monitoring in renal failure. Among the anti-Xa DOACs, edoxaban has about 50% renal clearance. Idarucizumab is the specific reversal agent for dabigatran (not rivaroxaban); andexanet alfa reverses anti-Xa DOACs.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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