<prompt> Which of the following is not an ESTER?AmethocaineBenzocaineProcaineBupivacaine  <response>: Ans. d Bupivacaine Ref. Lee anaesthesia 12th 591 Anaesthesia by Ajya yadav, 2nd, pg 105LOCAL ANESTHETIC AGENTSEstersAmidesAll metabolised by pseudocholinesterase except cocaineMetabolised in liverHigh chances of allergic reactionsLow chances of allergic reactionsUntable solutionStable solutionEg: Amethocaine TetracaineBupivacaineBenzocaineEtidocaineCocaineLignocaineChlorprocaineMepivacaineProcainePrilocaineHint: Letter Y appears twice in the name of ail amides, while it appears only once in esters.Local anesthetic agentsSubclassMechanism of ActionEffectsClinical ApplicationsPharmacokinetics, ToxicitiesAmidesLidocaineBlockade of sodium channelsSlows, then blocks action potential propagationShort-duration procedures- epidural, spinal anesthesiaParenteral-duration 30-60 min - 2-6 h with epinephrine - Toxicity: CNS excitationBupivacaineSame as lidocaineSame as lidocaineLonger-duration proceduresParenteral-duration 2-4 h. Toxicity: CNS excitation-cardiovascular collapsePrilocaine, ropivacaine, mepivacaine, levobupivacaine: like bupivacaineEsters ProcaineLike lidocainelike lidocaineVery short proceduresParenteral.duration 15-30 min-30-90 min with epinephrine. Toxicity: Like lidocaineCocaineSame as above also has sympa- thomimetic effectsSame as aboveProcedures requiring high surface activity and vasoconstrictionTopical or parenteral, duration l-2h Toxicity: CNS excitation, convulsions, cardiac arrhythmias, hypertension, strokeTetracaine: Used for spinal, epidural anesthesia, duration 2-3 h 