title: Myotoxic effects of levobupivacaine, bupivacaine and ropivacaine in a rat model.
abstract: OBJECTIVE
  The aim of this study is to histopathalogically compare the myotoxic effects of a single injection of levobupivacaine, bupivacaine and ropivacaine in rat skeletal muscle.
  
  
  METHODS
  Rats received intramuscular injections of 0.5% bupivacaine (Group B), 0.5% ropivacaine (Group R), 0.5% levobupivacaine (Group L), or 0.9% normal saline (Group SF) (30 rats/group). At two, 10 and 20 days, 10 rats from each group were sacrificed and muscle samples were examined for myotoxic effects using hematoxylin-eosin staining under a light microscope.
  
  
  RESULTS
  Muscle damage in Groups B, L and R was similar qualitatively. In samples taken two days after injection, the muscle damage in Group B was maximal [Damage score: 3.0 (2.0-3.0)], Group R had less damage than Group B [damage score: 2.0 (2.0-3.0)] and the damage in Group L was minimal [Damage score: 1.0 (1.0-2.0)]. In muscle samples taken 10 days after injection, there was no significant difference in muscle damage scores among Groups B, R and L. In muscle samples taken 20 days after injection, regeneration was complete, and muscle mass was histologically normal for each of the three groups (B, L and R).
  
  
  CONCLUSIONS
  Levobupivacaine's myotoxic effect is qualitatively similar to that seen (and previously reported) with bupivacaine and ropivacaine. Levobupivacaine was found to be quantitatively less myotoxic than bupivacaine and ropivacaine after a single intramuscular injection, only two days after injection. Myonecrosis developed after a single intramuscular injection of local anesthetic but was completely regenerated by the 20th day after injection.
authors.affiliation: Anesthesiology and Intensive Care Department, Erciyes University Kayseri,Turkey. drkaramehmet@gmail.com
authors.forename: Karamehmet
authors.initials: K
authors.lastname: Yildiz
authors.forename: Sukran Nergiz
authors.initials: SN
authors.lastname: Efesoy
authors.forename: Saim
authors.initials: S
authors.lastname: Ozdamar
authors.forename: Arzu
authors.initials: A
authors.lastname: Yay
authors.forename: Cihangir
authors.initials: C
authors.lastname: Bicer
authors.forename: Recep
authors.initials: R
authors.lastname: Aksu
authors.forename: Eser
authors.initials: E
authors.lastname: Kilic
mesh_terms: D000577:Amides / Q000008:administration & dosage / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects* / Q000031:analogs & derivatives; D005260:Female; D007273:Injections, Intramuscular; D000077554:Levobupivacaine; D018482:Muscle, Skeletal / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D000077212:Ropivacaine
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine; D000077554:Levobupivacaine; D002045:Bupivacaine