Before i continue, please bear in mind that i majored in Genetics, the DNA thingy, not pharmology nor chemistry. But i don't mind doing a small search, even it's just a add on knowledge for me.
Anyway, lets skip the word "generic", and concentrate on the hydrocodone.
Information is based on this website http://en.wikipedia.org/wiki/Hydrocodone
Let me summerise.
Hydrocodone is a semi-synthetic opioid derived from two of the naturally occurring opiates, codeine and thebaine. Hydrocodone is an orally active narcotic analgesic and antitussive.
It is basically a painkiller by reacting to some receptors in the brain/spinal cord. Add it to alcohol, and you will sleep like a log. Pregnant ladies, please do not consume it, because what ever effects on the fetus is unknown. Hey, you can even get addicted to it. So, i guess, its a controlled drug. There may have numerous side-effects too.
Its Systematic (IUPAC) name:
4,5a-Epoxy-3-methoxy-17-methylmorphinan-6-one tartrate (1:1) hydrate (2:5)
Mol. weight: 299.368
Molecular structure of a hydrocodone.
For more information, you can go to http://en.wikipedia.org/wiki/Hydrocodone for additional information.