- Oxycodone Participants will be asked to complete a pain diary for approximately 10 days and to stop taking their current pain medications the night before they are admitted o the GCRC. Once the patients present at the GCRC, they will be started on the IV PCA (Patient Controlled Analgesia) Oxymorphone to control their pain. Titration will take approximately a total of 8 hrs. At the end of the titration period, patients will be discharged home on OPANA ER. The oral dose will be calculated based on the IV PCA use. During the titration, patients' pain, vital and side effects will be assessed hourly until the 8th hour of the IV PCA titration.