Dear patient Percocet is combination of oxycodone and acetaminophen or paracetamol. Oxycodone is opioid drug which is centrally acting pain reliever and habit forming if taken for long time. It is very effective for back pain. It has side effects of respiratory depression,addiction and constipation. Paracetamol is nsaids group drug and increases effects of oxycodone. It has side effects of liver damage if taken in excess. Rare skin reaction is also noted. So combination has synergistic effect in pain relief. Dosage is one tablet twice a day initially and then as and when required. Avoid taking drug if you have asthma , cirrhosis or allergy. All the best.