I have done codeine a good bit through my life, and it is probably my favorite 'mellow' drug other than weed. I was first introduced to it by a high school friend, and I used to trade weed or speed or coke or whatever for it. At first, I would only have a pill or two, but I started taking it more and more. It was cheap so I did it several times a day, which didn't help.
After a while the pills were too much of a chore to choke down, so I busted them up and dissolved them in (as I recall) ringer's lactate to inject. For several months I shot up increasingly more and more until I was usually a stupefied zombie. What I remember best about this was the way just after I shot up everything white seemed green, desks, walls, paper, etc. Not a dark green, a sort of day-glo, brighter-at-the-edges green, kind of hard to look at directly. Not suprisingly I did very poorly in school that year.
Other codeine highlights: Passing out during choir recital on codeine, Liquid Ketocet and Xylezine(sp?) I shot up, and nearly living on the stuff working under the table shoveling gravel last summer. No more green (Or shooting it up) It just made me feel stoned-happy and a couple made it so I could get drunk off a couple beers. A sidenote: A friend almost died that summer from taking Codiene and Vetrinary Epilepsy medicine and driving. be careful mixing with other downers.
