A Comparison of the Dynamics and Pharmacokinetics of Ropivacaine 7.5??mg/mL with and without Epinephrine Used for Epidural Anaesthesia in Urological Surgery

Abstract

To investigate the effects of adding a vasoconstrictor to ropivacaine for epidural anaesthesia. This randomised, double-blind study included 44 adults scheduled for urological surgery. Patients received either 20mL ropivacaine 7.5 mg/mL (group R, n = 22) or 20mL ropivacaine 7.5 mg/mL plus epinephrine 5 mug/mL (group R+E, n = 22) epidurally. Sensory and motor blocks were assessed and the pharmacokinetics of ropivacaine determined. Haemodynamic responses and adverse events were recorded. Patients were followed up for a maximum of 14 days. The groups were similar with respect to epidural block characteristics. Only one patient in each group experienced inadequate blocks. Median onset of sensory block at surgically relevant dermatomes ranged between 5 and 10 minutes in both groups. No significant difference in onset time was observed between groups. Median duration of sensory block at relevant dermatomes ranged from 3.6 to 5.7h in group R and from 3.3 to 5.9h in group R+E. Haemodynamic changes were moderate and were not considered clinically relevant. The incidence of adverse events was similar between groups. Plasma concentrations of ropivacaine peaked around 30 minutes in both groups; the mean maximum concentration was slightly higher in group R (1.4 mg/L) than in group R+E (1.1 mg/L). Ropivacaine 7.5 mg/mL with and without epinephrine 5 mug/mL produced equally effective and well tolerated epidural anaesthesia in urological patients. The addition of epinephrine did not offer any pharmacodynamic or pharmacokinetic advantages over ropivacaine alone.