Study 767905/008 Extension Study: Alvimopan for Treatment of Opioid-Induced Bowel Dysfunction in Cancer Pain Subjects

Inclusion Criteria: * Completed GSK sponsored alvimopan (opioid-induced bowel dysfunction) OBD study for subjects with cancer-related pain, e.g. SB-767905/008. * Taking full agonist opioid therapy for cancer related pain. * Met entry criteria of OBD in original study and per investigator continues to require therapy for management of OBD. * Capable of completing paper questionnaires at the study visits. Exclusion Criteria: * Unable to eat or drink. * Taking opioids for management of drug addiction. * Unable to use only rescue laxatives provided. * Inappropriately managed severe constipation that puts subject at risk of complications. * Has gastrointestinal (GI) or pelvic disorder known to affect bowel transit. * Concomitant medication(s), medical condition, or clinically significant laboratory abnormality that could jeopardize subject and also contraindicate study participation.