Yeah I know it's used as an antihistamine to mediate unwanted side-effects from opiates or even as an antiemetic on it's own - but traditional sources will tell you that it can vastly potentiate the effects of opiates, so I wanted to know if THAT was it's purpose in the mix. Personally I'm of the belief that whatever potentiating effect it may have is purely psychological, reducing ill-effects, without enhancing positive ones, hence making the subjective experience more positive for the subject.
I'm curious about this topic now because I just saw a guy who literally ate a positively sacriligeous (over 800mg) amount of this with his dope because he couldn't afford to buy enough heroin to stop the pain. I told him next time he wants to be a ****** to drink DXM if robbing someone in place of throwing away the needle was his next option. He's doing fine on methadone now.