I dont know, supposedly your liver can only metabolize like 450 mg of it anyway. Dont drink grapefruit juice or take PPIs while trying to get codeine high as it will kill it. One of my first opiate highs was a bottle of mytussin AC or cherrytussin. The smell still makes me gag, but I got off pretty good and nodded. Last time I tried I hadnt had any heroin or other opiate for a month and drank two bottles of cherrytussin and I didnt even get a hint of an opiate feeling. I got an ever so slight anxiolytic effect. Pretty sad really.
My advice towards dosing is generally bad as I have an elephants tolerance even when not having used a drug for some time. Last summer I had been opiate free for maybe 6 months and I managed to drink an entire flask of 200ml of 5mg per ml oxycodone in 7 hours. Just a few tiny sips got me off at first, but as my body kicked into high gear I had to take huge swallows and then it was gone.