Could it be the apap in your meds, if your taking tylenol 3 or something??
IF it's the tylenol then that rules out alot of options as far as codien and hydrocodone, although you could try vicuprofen or something similar. Try a CWE to determine whether it's the APAP.
If it's the opiate itself causing the nausea then i would reccomend either talking to doc about a different medication or seeking out a good antiemetic or certain benzodiazepines that will help with the discomfort.
Opioids never hurt my stomach unless too much apap is involved..i once vomited after about 9 vicodin and a few beers..bad choice lol don't drink on apap!
Exactly my first suspect: APAP. But the Morphine has the same effect so it sounds like actually an opiate side effect. And why do you all assume they are smoking those pills? Oral ingestion means swallowing them as far as I understand.
CHCH: Have yourself checked out by a doctor for all the reasons listed above. Pancreas, gallbladder, stomach etc. Obviously opiates mess with your digestion so it is quite possible that you are only noticing the symptoms while under the influence. Or it could be something as simple as gas that you have a hard time expelling while on opiates. Better safe than sorry, IMO.. Good luck.