This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Substance Related and Addictive Disorders, Subject name: Psychiatry
[{'content': 'Naltrexone is used in opioid addiction because: \nSelect and explain. \nA. To treat withdrawal symptoms, B. To treat overdose of opioids and prevent respiratory depression, C. To prevent relapse in highly motivated patients, D. Has addiction potential; used for detoxification of opioid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The only indication for naltrexone in opioid dependence is relapse prevention in highly motivated patients. For opioid overdose Naloxone is used and not naltrexone. Naltrexone must be discontinued 48 to 72 hours prior to receiving opiate analgesia. Most of the adverse effects of naltrexone are gastrointestinal, including nausea, vomiting, and abdominal pain or discomfo', 'role': 'assistant'}]