In my experience, if you can cope with the horrendous houndings of the heavy, heavy histaminemian horripilations there is no clear ceiling dose for codeine. The following is as far from HR as it gets so - seriously - do not try this at home, kiddies... When I was younger, stupider and totally ignorant of harm reductionism I used to IV up to a gram of codeine at a time several times daily. I can promise you it's somewhat stronger than 300mg, or 400mg or even 900mg. It's also extremely dangerous and I'm quite frankly amazed I survived unscathed. Ignorance is bliss maybe. I always loved the histamine "rush" just as some love the morphinated equivalent. Most hate it but for some it's almost a bonus.
Also, the belief that it's the small amount of codeine that is converted to morphine in vivo is entirely responsible for the opiate effects has been correced more than once recently - here in BDD just last week for one. Morphine is a part of the effect but not the only one - or even the predominant one, as far as I know. Makes up about 15% of the Goodness locked away in codeine. There are a number of other metabolites some of which are active others less so. Codeine is itself active too - it works all on it's own snorted, plugged and IV before it gets a chance to metabolise to produce other Goodies. It can also be surprisingly addictive with heavy use but obviously not in the same league as most other opies.
