Oxycodone is one opioid painkiller. It can be used to treat severe pain, such as that which follows major surgeries, traumas, or malignant tumors. Oxycodone can only be bought online with a prescription. There are three types available: tablets with a slow release, ordinary pills and capsules, and a liquid to ingest. Injecting it is an additional choice, albeit this is often done in a hospital.