Levo-bupivacaine is administered by which of the following route:

B i.e. (Epidural) Bupivacaine is a potent cardiotoxic and long acting (duration of action 120-240 min) amide linked local anestheticQ. It is used for infiltration, nerve block, epidural and spinal anaesthesia of long duration. Epidural anaesthesia using bupivaine is very popular. Bupivacaine is drug of choice for labour analgesia. Bupivacaine is prone to prolong QTc interval and induce ventricular tachycardia or cardiac depression. So bupivacaine is contraindicated in IV regional anaesthesia. Maximum tolerable dose is 175 mg without epinephrine and 225mg with epinephrine. Commercial bupivacaine is a racemic mixture of 'R' & 'S' isomer. Levo bupivacine being 'S' isomer has less potential for toxicity and is as effective as racemic one. Bupivacaine is most potent & best agent for isobaric spinal anesthesia but cannot be used as surface (topical) anesthetic agent.Q Bupivacaine is contraindicated in regional IV anesthesia d/t fear of cardiac arrhythmiaQ. It can be used by following routes- IntrathecalQ - EpiduralQ - Peripheral nerve block All local anesthetics (LAs) bind & inhibit cardiac Na channels, but bupivacaine binds more avidly & longer than lignocaine. The bupivacaine R (+) isomer binds cardiac Na channels more avidly than S (-) isomer. This finding lead to development of levobupivacaine & ropivacaine. Inhibition of epinephrine - Stimulated CAMP formation by LAs could explain the refractoriness of bupivacaine cardiovascular toxicity to standard resuscitation measures. Programmed electrical stimulation elicit more arrythmias with bupivacaine & levobupivacaine then with lidocaine or ropivacaine. Bupivacaine is most cardiotoxic local anaesthetic, so it should not be used for Beir's block.Q It's cardiotoxicity is enhanced in pregnancy. Intravenous bupivacaine and etidocaine may cause severe cardiac reactions which are A.V. hea block Dysarythmias e.g. ventricular fibrillation. - Circulatory collapse & primary cardiac failure (bradycardia, pallor, sweating & hypotension) Amiodarone (drug of choice)Q and Bretylium is used to treat bupivacaine induced ventricular tachycardias. Epinephrine remains first choice drug in event of circulatory collapseQ.