This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 10/11/2007 Hypothesis: This is a safety and feasibility study to: 1. Explore patient satisfaction of a rapid opioid rotation, i.e., conversion from controlled release morphine or oxycodone to OPANA ER utilizing 24hrs IV PCA oxymorphone titration followed by 2 weeks OPANA ER titration to effect. 2. Determine whether patients safely tolerate a 24 hours of IV PCA titration. 3. Determine whether the trial can be continued WITH SUBSEQUENT SHORTER DURATIONS (6 HOUR AND 12 HOUR) of IV PCA titration with comparable outcomes.