This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anaesthesia
[{'content': 'Most commonly used local anaesthetics \nSelect and explain. \nA. Dibucaine, B. Bupivacaine, C. Prilocaine, D. Tetracaine', 'role': 'user'}, {'content': "Answer: B \nExplanation: BupivacaineBupivacaine is 2nd most commonly used local anaesthetic (after lidocaine)Bupivacaine has the highest local tissue irritancy amongst local anaestheticsIt is the most cardiotoxic local anaestheticLevobupivacaine (The S(-) enantiomer of bupivacaine) is less cardiotoxic and less prone to cause seizureConcentrations used for bupivacaine are:- Nerve block :0.5%, epidural: 0.25-0.5% and spinal: 0.5% Maximum safe dose is 2mg/kg without adrenaline and 3mg/kg with epinephrine(Refer: stoelting's pharmacology and physiology in anaesthetic practice, 5th edition, pg no.294)", 'role': 'assistant'}]