This medicine is used to treat extreme pain (such as due to cancer). Opioid analgesics are the drug class of oxycodone HCl (Oxycontin OP 10 mg). By affecting the brain, Oxycontin OP 10 mg changes how your body experiences and response to pain. If someone has not been taking opioids consistently and take an overdose then, it could result in death. Never take Oxycontin OP 10 mg to treat minor pain that will go away in a few days.