Clinical effects and maternal and fetal plasma concentrations of 0.5% epidural levobupivacaine versus bupivacaine for cesarean delivery

Background: Bupivacaine exists as a mixture of two enantiomers. levobupivac aine and dexbupivacaine. Data suggest that levobupivacaine has equal local anesthetic potency, with reduced potential for central nervous system and c ardiovascular toxicity. The present study compares the efficacy of 0.5% lev obupivacaine with 0.5% bupivacaine for epidural anesthesia in parturients u ndergoing elective cesarean delivery. Methods: Sixty healthy obstetric patients undergoing elective cesarean deli very with epidural anesthesia completed the study. Patients were randomized to receive 30 ml of either 0.5% levobupivacaine or 0.5% bupivacaine in a d ouble-blind fashion. The efficacy endpoint measures included onset, offset, and quality of anesthesia. Neonatal blood gas analyses, Apgar score determ inations, and neurobehavioral examinations were performed Venous samples fo r pharmacokinetic studies and serial electrocardiograms were obtained in 10 patients in each group. Results: Levels of sensory block, motor block, muscle relaxation, and overa ll quality of anesthesia did not differ between groups, The frequency of hy potension was 84.4% in the levobupivacaine group and 100% for the bupivacai ne group (P less than or equal to 0.053). No significant difference in obse rved maximum concentration of drug after dosing or area under the plasma dr ug concentration versus time curve were seen, The maximum concentrations we re 1.017 and 1.053 mu g/ml, and the areas were 4.082 and 3.765 h(mu g/ml) f or the levobupivacaine and bupivacaine groups, respectively. Umbilical vein -to-maternal vein ratios were 0.303 for the levobupivacaine group and 0.254 for the bupivacaine group, Conclusions: The use of epidural 0.5% levobupivacaine for cesarean delivery results In equally efficacious anesthesia compared with 0.5% bupivacaine, Pharmacokinetic parameters were similar in the two groups.