Does swiy mean robotussin gel caps? If so, swim
has experience with these. He doesn't like to just pop them as they hit all at once hard and its a bit overwhelming.
The main problem with the caps is that they contain sorbitol, which can induce nausea. Popping that many of them will be hard on your stomach, especially if you haven't eaten.
Swim took an entire container once (20 caps I think) and was fine at first, but then the room started spinning around him and he had to go run and projectile vomit into the toilet stall. (hehe). He thinks he may have been because he took them before eating and they hit while he was eating so he couldnt consume any more food as he was too fucked and was in a public place.
So yeah, most likely the sorbitol that is causing the problem, not some special irritant added to discourage recreational use (unless thats the only reason for the sorbitol, but swim thinks its there for some purpose).
Sorbitol is poorly digested by the body and can cause cell damage if too much is taken. Avoid gel caps and perform the DXM
extraction instead to save you problems. I think its also possible that the sorbitol is only in the gel cover itself and not the inside so if you take the time to squeeze the gel out of the caps you may not have a problem. Don't try chewing it out in your mouth, swim tried that once and it was disgusting.