Threats of Concomitant Use or Discontinuation of Cytochrome P450 2D6 Inhibitors The concomitant utilization of tramadol hydrochloride tablets with all cytochrome P450 2D6 inhibitors (e.g., amiodarone, quinidine) might cause an increase in tramadol plasma degrees plus a lower within the amounts of the active metabolite, M1.GOV.UK has a lot more info