Send to

Choose Destination
See comment in PubMed Commons below
Br J Anaesth. 1991 Sep;67(3):239-46.

Disposition of mepivacaine and bupivacaine enantiomers in sheep.

Author information

  • 1Department of Anaesthesia and Intensive Care, Flinders Medical Centre, Flinders University of South Australia, Adelaide, Australia.


Mepivacaine and bupivacaine are used clinically as racemic mixtures of enantiomers. In these studies the enantiomers of each agent were administered separately to sheep by i.v. bolus injection on separate occasions. Enantioselective disposition was deemed if the R:S ratio of the relevant pharmacokinetic parameter differed significantly from unity. Both enantiomers of both agents were cleared principally by the liver; urinary excretion of unmetabolized agents accounted for less than 2% of the doses. For R(-)-and S(+)-mepivacaine, respective mean (SEM) values of parameters were: total body clearance 1.20 (0.29) litre min-1 and 0.97 (0.20) litre min-1 (ns); total volume of distribution 144 (39) litre and 80 (21) litre (P less than 0.05); slow half-life 120 (40) min and 84 (22) min (ns); mean hepatic extraction ratio 0.50 (0.14) and 0.52 (0.09) (ns); mean hepatic clearance 0.75 (0.23) litre min-1 and 0.75 (0.18) litre min-1 (ns). For R(+)- and S(-)-bupivacaine, respective values were: total body clearance 0.77 (0.33) litre min-1 and 0.53 (0.26) litre min-1 (P less than 0.05); total volume of distribution 40 (10) litre and 43 (10) litre (ns); slow half-life 57 (10) min and 104 (21) min (P less than 0.05); mean hepatic extraction ratio 0.46 (0.15) and 0.29 (0.13) (P less than 0.05); mean hepatic clearance 0.85 (0.31) litre min-1 and 0.54 (0.26) litre min-1 (P less than 0.05). Thus there was enantioselective distribution of mepivacaine and enantioselective clearance of bupivacaine, but the magnitude of the effect was relatively small.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center