Study of the Effectiveness and Tolerability of OROS Hydromorphone HCI SR(Slow-release) Tablets and Immediate-Release Hydromorphone Tablets in Patients With Chronic Pain

Inclusion Criteria: * Patients who have chronic non-malignant or cancer pain currently receiving strong or transdermal opioid analgesics on a daily basis or patients suitable for advancement of therapy to step 3 on the WHO (World Health Organization) analgesic ladder * Patients who, at Visit 2, require the equivalent of at least 80 mg but no more than 300 mg of oral morphine sulfate (exclusive of breakthrough pain medication) every 24 hours or at least 25 micrograms an hour but no more than 75 micrograms an hour of Fentanyl * Patients must be on a stable dose of a strong opioid medication at Visit 2. Patients will be considered stabilized when the total daily dose of their prestudy opioid medication remains unchanged, with no more than three opioid breakthrough pain doses/day administered for breakthrough pain, for two consecutive days * Patients who can be expected to have reasonably stable opioid requirements for the duration of the study Exclusion Criteria: * Patients intolerant of or hypersensitive to hydromorphone (or other opioid agonists) * Patients who have difficulty swallowing or are unable to swallow tablets * Patients who are pregnant or breast-feeding. Female patients of child-bearing potential must be following a medically recognized contraceptive program prior to and during the study. A negative pregnancy test is required prior to administration of study drug * Patients with any gastrointestinal disorder, including pre-existing severe gastrointestinal narrowing that may affect the absorption or transit of orally administered drugs * Patients with any intracranial lesion, increased intracranial pressure, seizure disorder, stroke within the past 6 months, and disorders of cognition * Patients with clinically significant impaired kidney or liver function, thyroid disease, enlarged prostate, or urethral narrowing * Patients who may be at risk for serious decreases in blood pressure upon administration of an opioid analgesic