Oxycontin OC simply means Oxycontin Continuous, while Oxycontin OP simply stands for Oxycontin Purdue. Oxycontin OC is a typical new version of Oxycontin OP. The name used to be Oxycodone actually, it is a drug used for the treatment of severe and chronic pain. So, as time went by, the name was changed from Oxycodone to Oxycontin OC, and now we have Oxycontin OP. The Oxycontin OP is made with the same ingredients as Oxycontin OC, but just with some little additions.
The Oxycontin OP is harder, and not that easy to chew, unlike the Oxycontin OC. This is done so as to prevent the abuse of the previous version, which used to be chewed, snorted, or dissolved inside water, which in turn leads to the abuse of the drug. The Oxycontin OC drugs have the letters "OC" stamped on them, while the Oxycontin OP drugs have the letters "OP" embossed on them.