- Participants whose medication for chronic pain meets one of the criteria among a to e (2 or more types of opioid analgesics must not be used): a) Participants who are taking non-opioid analgesic at the normal highest dose or more for at least 14 consecutive days during 12 weeks before the informed consent, but were not continuously taking the non-opioid analgesic during 14 days before the informed consent for medical reasons such as safety b) Participants who are continuously taking an additional analgesic with a certain dosage and administration for at least 14 consecutive days before the informed consent c)Participants who are continuously taking codeine phosphate or dihydrocodeine phosphate less than 270 milligram (mg) daily (except for rescue treatment) for at least 14 consecutive days before the informed consent d) Participants who are continuously taking codeine morphine hydrochloride of oral morphine equivalent dose of less than 45 mg daily (except for rescue treatment) for at least 14 consecutive days before the informed consent (less than 30 mg daily for suppositories and less than 15 mg daily for injections) e) Participants who are continuously taking fentanyl citrate injection of less than 0.3 mg daily (except for rescue treatment) for at least 14 consecutive days before the informed consent