desvenlafaxine will boost the level or outcome of codeine by impacting hepatic enzyme CYP2D6 metabolism. Use Warning/Monitor. Desvenlafaxine inhibits CYP2D6; with bigger desvenlafaxine doses (ie, four hundred mg) minimize the CYP2D6 substrate dose by nearly fifty%; no dosage adjustment required with desvenlafaxine doses seven consecutive times inst