Longest acting L.A. – a) Bupivacaineb) Tetracainec) Xylocained) Procaine
Dibucaine is the longest acting LA (duration is 2.5-3.5 hours).
Amongst the given options tetracaine & bupivacaine are longest acting (both have duration of 2-3 hours).
Decreasing order of duration :- Dibucaine (longest acting) > Bupivacaine = Tetracaine = Ropivacaine = Etidocaine > Prilocaine = Lignocaine = Mepivacaine = Cocaine > Procaine > chlorprocaine.
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