, ritonavir) or discontinuation of a cytochrome P450 3A4 inducer like rifampin, carbamazepine, and phenytoin, may bring about an increase in codeine plasma concentrations with subsequently increased metabolism by cytochrome P450 2D6, causing increased morphine ranges, which could improve or extend adverse reactions and will cause perhaps fatal respiratory depression. https://louiskkjpv.answerblogs.com/32458360/5-essential-elements-for-akorn-promethazine-codeine