Levobupivacaine.

Bupivacaine has been the most widely used local anaesthetic for years. Recent studies point out levobupivacaine, an S(-) isomer of the racemic bupivacaine. This review shows the properties of levobupivacaine describing the animal and human volunteers studies on toxicity and the first clinical studies in obstetrics, general surgery and paediatrics. In vitro animal studies show that, injected intravenously, levobupivacaine has less cardiotoxic effects and less toxic effects on the CNS in comparison with both R(+) bupivacaine and bupivacaine itself, caused by a minor affinity for brain tissue resulting in less CNS depressant effects as well as for myocardial tissue, which leads to a higher dose necessary before being lethal in comparison to bupivacaine. Studies in human volunteers confirm these results, adding a minor arrhythmogenic, and less negative inotropic effect. Clinical studies show no significant differences in onset, duration and sensory block, but complete regression of sensory block takes longer. Potency is equal for levo- and bupivacaine according to MLAC in labour analgesia. Studies in paediatrics confirm effective analgesia but show less intensity of motor block. The reduced toxicity of levobupivacaine gives wider safety margin in the daily clinical practice both for single shot and for continuous infusion, intraoperatively during various surgical procedures and for the postoperative pain control and analgesia in labour.