FDA knows all about the cough syrup, kids
The FDA has noticed that kids everywhere are chugging cough syrup because they're making themselves sick: 8,000 kids ended up in the emergency room due to cough syrup abuse in 2008, which is up 70% from 2004. There's some talk of regulating the world's easiest drug for a high school kid to get, though making cough syrup prescription-only would be incredibly irritating during cold season. It might end up behind the counter, which would mean that you'd have to be 18 to buy it and would significantly compromise the offerings at many a drama club cast party.
In reading about kids drinking cough syrup, I found a wonderful Wikipedia entry, "Recreational use of dextromethorphan", the dissociative drug in many cough syrups, which is the last thing you should let any 16 year-old read if you're trying to prevent them from ladling this stuff onto their Cheerios.
A few excerpts from the various stages of intoxication one experiences on too much cough syrup:
* First plateau: effects include a sensation of alertness, stimulant effects such as restlessness, intensification of emotions, general euphoria, and euphoria linked to music.
* Second plateau: effects include entering a dreamlike state of consciousness, a heavier "stoned" feeling than with first plateau, and/or closed-eye hallucinations.
* Third plateau: effects include dreamlike vision, inability to comprehend language, abstract hallucinations, feelings of peace and quiet, and/or feelings of rebirth.
* Fourth plateau: an individual may experience a perceived loss of contact and control with their own body, out-of-body experiences, perceptions of contact with "superior," supernatural, or other archetypal beings (e.g. gods, aliens, vampires, etc.)
* Plateau Sigma: users have reported encounters with aliens and gods.
Maybe those last ones are only when you're on Ayahuasca-flavored Robitussen.
One clarification: the regular robo-tripping cough syrup that the FDA is concerned about is not the same as the stuff that southern rappers drink. That's drank. Sizzurp. Promethazine-codeine. Wikipedia has an extensive entry for that, too, with examples of about 35 different guys (and Nicki Minaj) who have referenced it in their songs. To be honest, prescription cough syrup doesn't sound nearly as crazy as the regular stuff, even if it can kill you: Wikipedia describes the high as "extreme somnolence" rather than vampire hallucinations.
No one seems to write songs about over-the-counter cough syrup, probably because its fans are mostly suburban 9th graders.