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
Addition of a vasoconstrictor along with LA causes ? 
Select and explain. 
A. More systemic toxicity, B. Fall in BP, C. Prolongation of duration, D. Reduced intensity of block
A: More systemic toxicity
Answer: A: More systemic toxicity 
Explanation: 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.