1, 7.two) ]. Threats of Concomitant Use or Discontinuation of Cytochrome P450 2D6 Inhibitors The concomitant utilization of Promethazine with Codeine Oral Option with all cytochrome P450 2D6 inhibitors (eg., amiodarone, quinidine) may perhaps end in an increase in codeine plasma concentrations and also a minimize in Energetic metabolite morphine pl