The original source of the molecules used to make these painkillers is the opium poppy. A molecule called thebaine is isolated from the opium poppy. Thebaine is then used to make many prescription painkillers.
Currently, fifteen countries legally grow opium poppies for use in pharmaceuticals. These include: Australia, China, France, Hungary, India, Japan, Spain, Turkey and the United Kingdom.
Oxycodone was first created by the German pharmaceutical company Bayer (the same one that makes aspirin) because they stopped selling heroin due to problems with addiction. It was hoped that a thebaine-derived drug would retain the painkilling effects of heroin with less of the euphoric high which leads to addiction. Unfortunately, this was not the case. When looking at the structures of thebaine, oxycodone, and heroin, it is easy to see that their structures are quite similar and therefore easy to believe their effects are similar. It is interesting to note that painkillers are considered the most abused prescription drugs in the United States. Also, painkillers (opioids) are one of the most prescribed class of drugs in the United States.
Strange Chemistry 