Yes it is two medications a friend tried this and got kicked out of clinic
They are all opiates meaning they test your urine for opium which all opiates contain.
It can take 4 to 5 days for cocaine and opiates to get out of your urine, but this may differ from one person to another.
None, there are no antihistamine-type opiates.
Hydrocodone is a synthetic opioid, and (oddly enough), many standard drug tests don't test for synthetic opiates such as hydrocodone, oxycodone, or fentanyl. The common tests usually test for morphine and codeine, which are the products of heroin. However, a doctor or employer can request a test specifically for synthetic opiates. Look here for more info: http://www.erowid.org/pharms/hydrocodone/hydrocodone_testing.shtml
opiates
Opiates.
Both of those are opiates
No
If you don't take them in the first place, you don't have to worry about getting them out of your urine.
Usually drug tests only test for the metabolite of opiates in your urine. So yes oxycodone will show up in a urine based drug test. Demerol being fully synthetic on the other hand may not.
they are both opiates but if its a lab and your positive for opiates they will test for the exact one.