- Participants currently receiving an inhibitor of cytochrome P450 family 2, subfamily C, polypeptide 8 (CYP2C8) (gemfibrozil, ketoconazole, quercetin, trimethoprim), or an inducer of CYP2C8 (cortisol, dexamethasone, phenobarbital, rifampin), or cytochrome P450 family 3, subfamily A, polypeptide 4 (CYP3A4) substrate