Abstract
Concomitant use of apixaban and carbamazepine (CBZ) is not recommended due to an anticipated reduction in apixaban concentration, although few case reports describe this interaction. We report a case of initiating apixaban 10 mg twice daily (BID), in a patient stabilized on CBZ 600 mg BID that was guided by prior experience. Apixaban concentrations were substantially elevated with initial empiric dosing; apixaban dosing of 7.5 mg BID was eventually implemented. This case highlights the fact that the degree of induction by CBZ can vary, regardless of the dose, and requires clinicians to be cautious when applying prior experiences with patients to new patients.