This is a pilot study to determine the pharmacokinetics of (R,S) methadone in adolescents. A total of approximately 15 patients will be required. The purpose is to determine the levels of R, S methadone at various time intervals after drug administration. Patients will receive methadone 0.25 mg/kg IV at induction and a standardized anesthetic of remifentanil and propofol. At the conclusion of surgery (45 minutes prior to the completion), the patients will receive a loading dose of morphine based on respiratory rate. A morphine PCA will be utilized for postoperative analgesia. Pharmacokinetic data will be collected in addition to VAS scores, patient and parental satisfaction with analgesia, and a functional pain assessment.