There's conflicting advice about potentiating codeine on this forum, because unlike most other opiates its a 'pro drug',. meaning it has to me metabolised via the liver into morphine.
Some here say take GFJ before your codeine...some say take it after
because it blocks the livers conversion into morph. The same goes with other opiate potentiators such as promethazine, cemitedine etc.
Personally I go with the grape fruit before the codeine, & (on the rare occasion I use it, promethazine/tagemat etc) after the codeine has kicked in. This method seems to work for me, but perhaps it varies from person to person..
8)What you won't get on this forum is a DEFINATE/CERTAIN answer to this....its probably the most contentious issue here. lol