Abstract
Levobupivacaine is a levoisomer of bupivacaine, a long-acting, amide-type local anesthetic. This stereoisomer has less central nervous system and cardiovascular toxicity than racemic bupivacaine (bupivacaine) , as shown by the larger dose required to induce central nervous system and cardiovascular toxicity such as convulsions, hypotension and cardiac arrest. Its threshold plasma concentration for inducing those symptoms is also higher than bupivacaine. Central nervous system and cardiovascular toxicity of levobupivacaine is similar to those of ropivacaine. In an experiment using awake, spontaneously breathing rats, plasma concentrations of bupivacaine and levobupivacaine after intravenous infusion are superimposable, suggesting that the pharmacokinetics of the two stereoisomers of bupivacaine are similar. A microdialysis study has shown that the concentrations of bupivacaine in the cerebral extracellular fluid are higher than levobupivacaine, suggesting that those might be responsible for the higher central nervous system toxicity of bupivacaine.
