A comparison of the cardiovascular effects of levobupivacaine and rac-bupivacaine following intravenous administration to healthy volunteers

Abstract

Aims: The aim of this study was to compare the cardiovascular effects of levobupivacaine with those of rac-bupivacaine following i.v. administration to 14 healthy male volunteers. Methods: Drugs were infused (at 10 mg min-1) using a randomized, double-blind, complete crossover procedure with a washout period of at least 1 week. The administration of drug was discontinued on the appearance of defined CNS symptoms or when a total of 150 mg had been given. Parameters measured were artorial blood pressure, heart rate, EGG, ejection fraction, acceleration index, stroke index and cardiac index. Results: The mean doses administered were 56.1 mg and 47.9 mg for levobupivacaine and rac-bupivacaine respectively and the maximum mean plasma concentrations were 2.62 and 2.25 μg ml-1 respectively. Despite the dose and plasma concentrations being comparable, levobupivacaine produced a statistically significant smaller reduction in mean stroke index (-5.14 vs -11.86 ml m-2, P=0.001), acceleration index (-0.09 vs -0.20 s-2, P=0.011) and the ejection fraction (-2.50 vs -4.29%, P=0.024). Both levobupivacaine (non significant) and rac-bupivacaine (significant) produced small increases in the PR interval and the corrected QT interval and although the effects of rac-bupivacaine appeared to be greater the difference between the two drugs was not significant. Conclusions: In conclusion, this study has shown that following i.v. administration levobupivacaine produces significantly less effects on cardiovascular function than does rac-bupivacaine. In particular the negative inotropic effect for levobupivacaine was less than that for rac-bupivacaine as indicated by changes in stroke index, acceleration index and ejection fraction.