An orogastric tube will be placed in the stomach under anesthesia as is part of standard routine clinical care to remove gastric contents. The same orogastric tube will be used for intragastric liquid oxycodone administration in a dose of 0.1 mg/kg before the surgical incision. This weight-adjusted dose of 0.1 mg/kg is administered as per standard clinical dosing guidelines. 10 blood samples (51mL/sample) will be taken from the IV and sent for drug-level analysis. A total of 11 blood samples will be drawn for the study. The first sample will be sent for genetic testing. The other 10 samples will be drawn at the following time points: 30 minutes, 1, 1.5, 2, 3, 4, 5, and 6 hours post-dose in every patient and the other 2 samples anytime between 6 and 24 hours post-dose .