desvenlafaxine will raise the level or impact of codeine by impacting hepatic enzyme CYP2D6 metabolism. Use Caution/Keep an eye on. Desvenlafaxine inhibits CYP2D6; with bigger desvenlafaxine doses (ie, 400 mg) lessen the CYP2D6 substrate dose by up to fifty%; no dosage adjustment wanted with desvenlafaxine doses 7 consecutive times promptly prior t