Order Oxycodone Online is used to treat pain that is severe enough to require opioid treatment and when other pain medications are ineffective or cannot be tolerated. It belongs to the class of medications known as narcotic analgesics (pain medicines). Oxycodone relieves pain by acting on the central nervous system (CNS). Oxycodone extended-release capsules or tablets should not be used if you only need pain medication for a short period of time, such as after surgery. This medication should not be used to treat mild pain or in situations where non-narcotic medications are effective.