This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
[{'content': 'The use of Naltrexone in opioid dependence is in which phase of treatment? \nSelect and explain. \nA. Prevent respiratory depression, B. To treat withdrawal symptom, C. To prevent relapse, D. To treat overdose of opioid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Naltrexone is a long acting opioid antagonist. It is used in patients of opioid dependence for detoxification and withdrawal. It discourages substance seeking behaviour and thus prevents relapse. It can cause withdrawal symptoms in addicts due to blockage of opioid receptors. Ref: Kaplan & Sadock Synopsis of Psychiatry 9th Edition, Page 1082-87, 448-456; A sho textbook of Psychiatry by Neraj Ahuja 5th Edition, Page 45-48; Essentials of Pharmacology by K D Tripathi 5th Edition, Page 425; Shoer Oxford Textbook of Psychiatry 5th Edition, Page 358-361', 'role': 'assistant'}]