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
All are surface anaesthetics except - 
Select and explain. 
A. Lignocaine, B. Bupivacaine, C. Procaine, D. Cinchocaine
B: Bupivacaine
Answer: B: Bupivacaine 
Explanation: Ans. is 'b' i.e., Bupivacaine o Topical anaesthesia (surface anaesthesia) is produced by topical application of local anaesthetics to mucous membrane or abraded skin. o Surface anaesthetics are Dibucaine (Cinchocaine) Lignocaine Benoxinate Oxethazaine Prilocaine Tetracaine (Amethocaine) Cocaine Benzocaine Butamben o Procaine has very less potent surface anaesthetic action (1/10) --> not used as surface anaesthetic. o But amongst the given options best answer is bupivacaine, it does not have surface anaesthetic action.