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
Percentage of lidocaine in eutectic mixture 
Select and explain. 
A. 1%, B. 2.55, C. 5%, D. 10%
B: 2.55
Answer: B: 2.55 
Explanation: Eutectic mixture of local AnaestheticsThis is unique topical preparation which can anaesthetize the intact skinIt is a mixture of 2.5% lidocaine and 2.5 prilocaineIt acts slowly and the cream must held in contact with skin for at least 1 hourEMLA is used: to make venepuncture painless especially in children, and for the procedure like skin grafting & circumcision As systemic absorption of prilocaine can cause methemoglobinemia, EMLA should not be used on mucocutaneous membrane or in the very small child.(Refer: Morgan and Mikhail's Clinical Anaesthesiology, 5th edition, pg no. 754, 856)