desvenlafaxine will improve the stage or outcome of codeine by influencing hepatic enzyme CYP2D6 metabolism. Use Caution/Keep an eye on. Desvenlafaxine inhibits CYP2D6; with greater desvenlafaxine doses (ie, 400 mg) reduce the CYP2D6 substrate dose by up to 50%; no dosage adjustment necessary with desvenlafaxine doses 7 consecutive times quickly ju… Read More