 Lubiprostone is also approved to treat opioid-induced constipation, in adults with chronic non-cancer pain.The effectiveness of lubiprostone has not been established in patients who are taking a diphenylheptane opioid (e.g., methadone).Lubiprostone is approved to treat irritable bowel syndrome with constipation (IBS-C) in women 18 years of age and older.