The concomitant utilization of TYLENOL® with Codeine with all CYP3A4 inducers or discontinuation of the CYP3A4 inhibitor may cause reduced codeine degrees, larger norcodeine amounts, and less metabolism by means of CYP2D6 with resultant lessen morphine amounts. Your doctor or pharmacist offers you the maker's patient facts sheet (Medication Information) https://wockusa.com/product/fentanyl-powder/