Vasomotor effect after acute intoxication with bupivacaine and levobupivacaine in rats via intraperitoneal route analyzed via digital infrared imaging.

BACKGROUND AND OBJECTIVES The study of the vasomotor effect of local anesthetics (LA) is of paramount importance for the analysis of the occurrence of cardiotoxic and neurotoxic effects, and drug interactions. In order to find a safer drug than racemic bupivacaine, this study aimed to analyze digital infrared imaging of acute vasomotor effect of bupivacaine and levobupivacaine in rats intraperitoneally. METHOD We used 30 male Wistar rats distributed into three groups (n=10) and subjected to an intraperitoneal injection of LA. In Group C (control) 1 mL 0.9% saline was injected intraperitoneally. In Group B (bupivacaine), intraperitoneal injection of 0.5% of racemic bupivacaine (S50-R50), dose of 20 mg.kg⁻¹ of body weight. In Group L (levobupivacaine), intraperitoneal injection of levobupivacaine 0.5% enantiomeric excess (S75-R25) in dose of 20 mg.kg⁻¹ of body weight. The procedure was thermographicly continuously filmed from the time of pre-injection until 30 minutes after injection. The results of the recordings were analyzed in graphical form, verifying the maximum temperature of each rat and the average temperature of the system that housed the animal. RESULTS The results of graphic analysis showed no difference between Group L and Group C, and the average temperature remained stable throughout the experiment in both groups. In Group B, there was a phenomenon of temperature increase after intraperitoneal injection of bupivacaine. CONCLUSIONS The results demonstrated that the vasomotor effect of the acute toxicity of levobupivacaine was similar to Group C with saline, through macroscopic studies by infrared digital filmmaking, and that there were vasomotor changes (vasoconstriction), with bupivacaine intoxication in relation to both Group C and Group L.