In clinical studies, lasofoxifene did not alter the metabolism of dextromethorphan (CYP2D6 substrate) and chlorzoxazone (CYP2E1 substrate) or the pharmacokinetics of warfarin (CYP2C9 substrate), methylprednisolone (CYP3A4 substrate) or digoxin (MDR1 P-glycoprotein substrate).