ritlecitinib will raise the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Check Intently. Ritlecitinib inhibits CYP3A4 substrates; coadministration boosts AUC and peak plasma concentration sensitive substrates, which may increase risk of adverse reactions.nalbuphine decreases effects of fentany