This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
[{'content': 'Which of the following adverse effects is characteristically associated with methysergide? \nSelect and explain. \nA. Pulmonary hypeension, B. Retroperitoneal fibrosis, C. Hepatotoxicity, D. Ischemic hea disease', 'role': 'user'}, {'content': 'Answer: B \nExplanation: All ergot derivatives can cause fibrosis on long term use. Due to risk of retroperitoneal fibrosis, methysergide should never be given continuously for more than 6 months.', 'role': 'assistant'}]