​Percocet is one of the most trusted painkillers on the market. It's used to treat moderate to severe pain and stiffness, as well as relief anxiety and depression in adults. It is used to treat moderate to severe pain that is caused by arthritis, gout, arthritis of the hip or knee, back pain . A prescription drug called Percocet is used to treat moderate to severe pain. It contains oxycodone and paracetamol, two of its active ingredients. Acetaminophen is a non-opioid pain reliever, whereas oxycodone is an opioid pain reliever.