this might quite possibly be the dumbest fucking thing I have heard (read) someone say in a long time. "hey instead of taking something that was manufactured in a sterile lab and thoroughly tested, why don't you just take these pills that some guy whipped up in his pill factory in miami." fucking idiot.
to the op - there is a lot of terrible information in this thread. The promethazine has no effect on you being fucked up. The codeine is why syrup makes you feel wonderful. if you are allergic to codeine then you would be a moron for drinking some syrup. i don't know how bad your allergy is but it could potentially kill you. Along those lines, hydrocodone is basically synthetic codeine so I'd be careful with that too. Like I said, it could kill you. It sure would suck if your allergic reaction amplified the depressing effects of the opiate and made your heart stop. something to think about.
If you want to take some opiates to get your lean on, order yourself some tramadol. It is basically a non-opiate that acts on the brain in a similar manner as opiates...i.e. it binds to the same receptors in your brain as the opiates do to give you the feeling of "pain relief". There are a couple of nice things about this - it virtually feels exactly like popping a handful of vicodin, (smoke a phatty and it'll send you thru the floor) and it doesn't pop on a drug test as an "opiate".
Here's the best part....you can order it right off of the internet since it's not considered a controlled substance...meaning you still need a "prescription" for it, but it doesn't carry the same legal status as vicodin, percs, morphine, cocaine, heroin, etc.