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': 'Addition of a vasoconstrictor along with LA causes ? \nSelect and explain. \nA. More systemic toxicity, B. Fall in BP, C. Prolongation of duration, D. Reduced intensity of block', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'c' i.e., Prolongation of duration Vasoconstrictor Remember o Adrenaline is the most commonly used vasoconstrictor. o Felypressin (synthetic vasopressin) is an alternative. It does not affect BP and HR --> preferred in patients with cardivascular disease. - o Vasoconstrictor should not be added for ring block of hands, feet, finger, penis and in pinna --> All these organs are supplied by endaeries.", 'role': 'assistant'}]