Ritonavir or lopinavir/ritonavir considerably increase plasma concentrations of oxycodone in nutritious human volunteers because of inhibition of CYP3A4 and CYP2D6.[58] Rifampicin enormously decreases plasma concentrations of oxycodone due to powerful induction of CYP3A4.Before using PERCOCET, notify your Health care provider In case you have a rec