Ropivacaine myotoxicity after single intramuscular injection in rats.
OBJECTIVE
We conducted this study in order to evaluate the potential myotoxic effects of ropivacaine after single injection in rats and the time-course of the possible damage.


METHODS
One hundred and twenty-eight male Wistar rats were allocated to four different groups. The first three groups received intramuscular injections with ropivacaine 0.75%, ropivacaine 0.5% and normal saline, respectively, into the right tibialis anterior muscle. The fourth group received needle puncture without injection. Eight rats from each group were sacrificed 2, 4, 7 and 30 days after injection. Samples were blindly examined under light microscope for evidence of myotoxicity, scored as 0 = no damage to 3 = myonecrosis and statistically analysed. Samples obtained 7 days after injection were also examined under transmission electron microscope.


RESULTS
Ropivacaine 0.75% and ropivacaine 0.5% caused extensive destruction to muscles fibres, compared to saline or needle on days 2, 4 and 7. Statistically significant differences were found in muscle damage by drug injections among all groups except for saline vs. needle groups. Thirty days after injections all sample appearances had returned to normal.


CONCLUSIONS
Ropivacaine after single intramuscular injection caused reversible muscle damage in a dose-dependent manner.
Amaniti
E
E
Aristotle University of Thessaloniki, School of Medicine, AHEPA University Hospital, Anaesthesiology Department, Thessaloniki, Greece. kkioup@otenet.gr
Drampa
F
F
Kouzi-Koliakos
K
K
Kapoukranidou
D
D
Pourzitaki
C
C
Tsalie
E
E
Vasilakos
D
D
D000577:Amides / Q000008:administration & dosage / Q000633:toxicity*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006614:Hindlimb; D007273:Injections, Intramuscular; D008297:Male; D046529:Microscopy, Electron, Transmission; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D009336:Necrosis; D051381:Rats; D017208:Rats, Wistar; D000077212:Ropivacaine
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine