Most cardiotoxic local anesthetic -

Ans. is 'b' i.e., Bupivacaine o Bupivacaine is the most cardiotoxic LA (Ropivacaine is a newer bupivacaine congener with less tardio toxicity).Important facts about LAso Chlorprocaine is the shortest acting LA.o Dibucaine is the longest acting, most potent and most toxic LA.o Procaine & chlorprocaine are least potent LAs.o Bupivacaine is the most cardiotoxic L4 (Ropivacaine is a newer bupivacaine congener with less cardiotoxicityi)o Levobupivacaine (The S (-) enantiomer of bupivacaine) is less cardiotoxic and less prone to cause seizure.o Prilocaine and Benzocaine can cause Methaemoglobinemiao Lignocaine is the most commonly used LAo Bupivacaine has the highest local tissue irritancy:o Chlorprocaine is contraindicated in spinal anaesthesia as it can cause paraplegia due to presence of neurotoxic preservative sodium metabisulphite.o Procaine is the LA of choice in malignant hyperthermia.