one, 7.two) ]. Challenges of Concomitant Use or Discontinuation of Cytochrome P450 2D6 Inhibitors The concomitant usage of Promethazine with Codeine Oral Solution with all cytochrome P450 2D6 inhibitors (eg., amiodarone, quinidine) may lead to an increase in codeine plasma concentrations in addition to a minimize in Lively metabolite morphine plasm… Read More