Grapefruit Juice (GFJ)- I'd toyed with the concept of making use of grapefruit juice for a very long time but have read through combined stories. A short while ago I examine that it doesn't inhibit CYP2D6 but rahter 3A4 which can be chargeable for conversion of codeine into norcodeine. In idea by inhibiting 3A4 you allow a lot more codeine for 2D6