Effects of bupivacaine and ropivacaine on hemodynamic parameters in rabbits

In the present study the toxic effects of ropivacaine and bupiavacaine on t he cardiovascular and respiratory systems of rabbits were studied. Both dru gs were administered intravenously at doses of 0.5, 1, 2.5, 5 and 10 mu mol /kg. The effects of the two drugs on blood pressure, ECG and respiration ra te were evaluated by considering the changes occurring 30 sec after intrave nous bolus injection. High doses (5 and 10 mu mol/kg) of bupivacaine and ro pivacaine significantly reduced the heart rate and systolic pressure (p < 0 .05). Five and 10 mu mol/kg of bupivacaine significantly reduced diastolic pressure (p < 0.05), but only the 10 mu mol/kg dose of ropivacaine had the same effect. Low doses of bupivacaine and high doses of ropivacaine signifi cantly increased the PR interval, QRS duration and QT interval (p < 0.05). The 5 mu mol/kg dose of bupivacaine caused ventricular tachycardia in 3 of 6 rabbits, whereas ropivacaine caused tachycardia in 1 of 5 rabbits. Neithe r drug had a significant effect on respiration rate or blood gas values (p > 0.05). The results indicate that ropivacaine is less cardiodepressive and arrhythmogenic than bupivacaine. (C) 2001 Prous Science. All rights reserv ed.