Grapefruit Juice (GFJ)- I'd toyed with the idea of working with grapefruit juice for a long time but have read mixed reviews. A short while ago I read that it does not inhibit CYP2D6 but rahter 3A4 which happens to be answerable for conversion of codeine into norcodeine. In principle by inhibiting 3A4 you leave much more codeine for 2D6 to turn int