Arrange the following long acting LA in descending order of their duration of action.: (A) Dibucaine>Etidocaine>Tetracaine> Bupivacaine., (B) Dibucaine>Tetracaine>Bupivacaine> Etidocaine., (C) Tetracaine>Dibucaine>Bupivacaine>Etidocaine., (D) Tetracaine>Bupivacaine>Dibucaine> Etidocaine.
Answer is A. Dibucaine is longest acting and most toxic.
Etidocaine: 200minutes.
Tetracaine~Bupivacaine:175 minutes.