Opioid-induced Bowel Dysfunction: Long-Term Assessment of Lubiprostone

Inclusion Criteria: * Has completed 12 weeks of blinded treatment in NCT00595946 or NCT00597428 * Will continue to be treated consistently for chronic, non-cancer-related pain with any full agonist opiate and will continue opiate therapy for the duration of the study * Willing to continue to abstain from use of disallowed medications as defined per protocol Exclusion Criteria: * Has newly diagnosed impaired renal function identified at the Screening Visit \[i.e., serum creatinine concentration \> 1.8 milligrams per deciliter (mg/dL)\] * Has experienced an unexplained and/or clinically significant weight loss defined as \> 5% within 90 days prior to Screening Visit. * Has plans to participate in another trial with an investigational drug or device during the course of the extension study