Percocet's generic name Oxycodone-Acetaminophen is used to relieve body pain from moderate to severe.Percocet is a pain killer medicine containing two drugs-Oxycodone and Acetaminophen. It gives relief for about 5 hours when taken as prescribed. One might ask how long does percocet stay in your system, so it can stay in the urine for 1 to 3 days, in the blood for 24 hours, and in the hair follicle for up to 30 days. Some side effects of percocet are: Dizziness, headache,nausea, vomiting, dry mouth, itching.