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': 'What is the mechanism of action of use of Naltrexone in alchohol addiction in a 45-year-old man? \nSelect and explain. \nA. Inhibits metabolism of alcohol, B. Blocks opioid receptors, C. Affects GABA neurotransmitter system, D. None of the above', 'role': 'user'}, {'content': "Answer: B \nExplanation: Naltrexone blocks opioid receptors and reduces craving for alcohol and opioids. It also reduces reward in response to drinking. Hence it is useful to prevent relapse in a de-addiction programme. Inhibits metabolism of alcohol: Disulfiran inhibits metabolish of alcohol and leads to accumulation of acetaldehyde. Affects GABA neurotransmitter system: Acamprosate affects GABA and Glutamate neurotransmitter system. Ref: Kaplan & Sadock's Synopsis of Psychiatry, By Benjamin J Sadock, M.D., Harold I. Kaplan, Virginia A Sadock, M.D, 10th Edition, Page : 406", 'role': 'assistant'}]