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: Pharmacology
[{'content': 'A drug given for metoclopramide induced dystonic reaction is : \nSelect and explain. \nA. Pheniramine, B. Promethazine, C. Chlorpromazine, D. Prochlorperazine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "Acute muscle dystonia caused by antiemetic-antipsychotic drugs is promptly relieved by parenteral promethazine or hydroxyzine." This is based on the central anticholinergic action of the drugs.\nPromethazine is a first-generation anti-histaminic which has a maximum penetration of blood-brain barrier and maxi\xadmum anticholinergic activity.', 'role': 'assistant'}]