Percocet is an opioid medication for the treatment of moderate to severe pain, and a common medicine of abuse. It also treats lower abdominal pain. Its consumption is by mouth and is available in immediate-release and controlled-release formulations. Wikipedia Formula: C18H21NO4 Molar mass: 315.364 g/mol Onset of action: IR: 10–30 minutes; CR: 1 hour Duration of action: By mouth (IR): 3–6 hrs; By mouth (CR): 10–12 hrs Elimination half-life: By mouth (IR): 2–3 hrs (same t1/2 for all ROAs); By mouth (CR): 4.5 hours.