This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Local and Regional Anesthesia), Subject name: Anaesthesia
[{'content': 'Percentage of lidocaine in Eutectic mixture - \nSelect and explain. \nA. 1%, B. 2.50%, C. 5%, D. 10%', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 2.5% Eutectic mixture of local Anaesthetics o This is unique topical preparation which can anesthetize intact skin. o It is a mixture of 2.5% lidocaine and 2.5 prilocaine. o It acts slowly and the cream must be held in contact with the skin for at least 1 hour. o EMLA is used: to make venepuncture painless especially in children, and for procedures like skin grafting & circumcision. o As systemic absorption of prilocaine can cause methemoglobinemia, EMLA should not be used on mucocutaneous membrane or in a very small child.", 'role': 'assistant'}]