<prompt> Addition of a vasoconstrictor along with LA causes ?More systemic toxicityFall in BPProlongation of durationReduced intensity of block  <response>: 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. 