Open-Label Trial Comparing Oxycodone Medications

The investigators hypothesize that subjects will have greater pain relief when taking IR-oxycodone compared with ER-oxycodone for several reasons. The ability to take a varying amount of medication at six different points over the course of a day will allow patients to take as much (or as little) medication as they need to control their pain. In addition, the ability to vary the medication doses in this way will give them a greater sense of control, which will also contribute to greater pain relief. Similarly, the investigators predict that patients will show greater benefits with IR-oxycodone on the measures of physical and emotional functioning. Because there is relatively little data on sleep apnea in chronic pain patients (Webster et al., 2008), these assessments are exploratory and not hypothesis-based. Finally, although it is typically thought that the abuse liability of IR-opioid medications is greater than for ER-medications, the data on which this belief are based have not involved systematic studies of patients with chronic pain; the assessments of abuse liability will therefore also be exploratory.