ribociclib will boost the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism.enzalutamide will lower the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead on into a minimize in fentanyl p