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': 'Which of the following is the most potent 2nd generation antihistamine? \nSelect and explain. \nA. Astemizole, B. Desloratadine, C. Promethozine, D. Fexofenadine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Desloratidine, metabolite of loratadine\xa0is the most potent 2nd generation antihistamine.', 'role': 'assistant'}]