Study to Evaluate the Long-Term Safety of Hydrocodone Bitartrate Extended-Release Tablets (CEP-33237) in Patients Who Require Opioid Treatment for an Extended Period of Time

Inclusion Criteria: * The patient must be willing and able to successfully self-administer the study drug, comply with study restrictions, and return to the clinic for scheduled study visits as specified in this protocol. * The patient has either completed Cephalon study 3079 or has chronic pain of at least 3 months duration prior to entering this study associated with any of the following conditions: diabetic peripheral neuropathy, postherpetic neuralgia, traumatic injury, complex regional pain syndrome, back pain, neck pain, osteoarthritis, or rheumatoid arthritis. Patients with other painful conditions may qualify for the study with permission from the Cephalon medical monitor or designee. * Those patients who completed the 12-week, double-blind, placebo-controlled, randomized study (study 3079) and are willing to re-titrate study drug to an effective dose of hydrocodone extended-release tablets are eligible to enter this study. * The patient is able to speak English, willing to provide written informed consent, and sign a written opioid agreement, to participate in this study. * The patient is 18 through 80 years of age (inclusive) at the time of entering this or the previous study (study 3079). * Women of childbearing potential (not surgically sterile or 2 years postmenopausal), must use a medically accepted method of contraception and must agree to continue use of this method for the duration of the study and for 30 days after participation in the study, and have a negative pregnancy test at screening. Exclusion Criteria: * Patients who were enrolled in study 3079 but did not complete the 12-week, double-blind, placebo-controlled, randomized study may not be enrolled into this study. * The patient has known or suspected hypersensitivities, allergies, or other contraindications to the study drug or its excipients. * The patient has a recent history (within 5 years) or current evidence of alcohol or other substance abuse. * The patient has a medical or psychiatric condition/disease that, in the opinion of the investigator, would compromise collected data. * The patient is taking a total (i.e., including around-the clock \[ATC\] and rescue medications) of more than 135 mg/day of oxycodone or equivalent for 14 days prior to screening. * The patient has a history of suicidality. * The patient has a diagnosis of chronic headache or migraine as the primary painful condition under study. * The patient is expected to have surgery during the study and it is anticipated that the surgery will alleviate the patient's pain. * The patient is pregnant or lactating. * The patient has active malignancy. * The patient has human immunodeficiency virus (HIV). * In the judgment of the investigator, the patient has any clinically significant deviation from normal in the physical examination and/or clinical laboratory test values. * The patient has cardiopulmonary disease that would, in the opinion of the investigator, significantly increase the risk of treatment with potent synthetic opioids. * The patient has participated in a study involving an investigational drug in the previous 30 days (excluding those who participated in study 3079). * The patient has received a monoamine oxidase inhibitor (MAOI) within 14 days before the first treatment with study drug. * The patient has any other medical condition or is receiving concomitant medication/therapy (e.g., regional nerve block) that would, in the opinion of the investigator, compromise the patient's safety or compliance with the study protocol, or compromise collected data. * The patient is involved in active litigation in regard to the chronic pain currently being treated. * The patient has a positive urine drug screen (UDS) for an illicit substance or medication not prescribed by the physician currently treating the chronic pain. * The investigator feels that the patient is not suitable for the study.