Preference for Subutex® (Buprenorphine) Versus Suboxone® (Buprenorphine/Naloxone) in Opioid Dependent Patients on Subutex® (Study P05094)(COMPLETED)

Inclusion Criteria: * Subject must demonstrate their willingness to participate in the study and comply with its procedures by signing a written informed consent. * Subject must be at least (\>=) 18 years of age, of either sex. * Subject treated for opioid dependence with Subutex® with a stable daily dose between 2 mg and 16 mg daily, for at least 6 months. * Subject who do not inject/misuse their treatment with Subutex®. * Subject must be free of illicit opiate drug use as assessed by urine test performed prior to inclusion. * Subject must understand and be able to adhere to the dosing and visit schedules, and agree to report concomitant medications / products and adverse events to the investigator or designee. * Women of childbearing potential (includes women who are less than one year postmenopausal and women who become sexually active) must be using or agree to use an acceptable method of birth control (e.g., hormonal contraceptive, medically prescribed IUD, condom in combination with spermicide) or be surgically sterile (e.g., hysterectomy or tubal ligation). * Women of childbearing potential should be counseled in the appropriate use of birth control while in this study. Women who are not currently sexually active must agree and consent to use one of the above-mentioned methods should they become sexually active while participating in the study. Women of childbearing potential must have a urine pregnancy test with negative result within 2 weeks prior to inclusion (as p…