Effects of epidural clonidine to lidocaine solution upon the requirements of sedatives during epidural anesthesia

The authors studied 34 patients undergoing abdominal total hysterectomy in order to evaluate whether epidural clonidine added to lidocaine solution could alter the requirements of sedatives during epidural anesthesia. Patients were randomly assigned to one of four groups; 18 ml of 2% lidocaine with 1:200,000 clonidine (n = 6), 1:100,000 clonidine (n = 7), 1:200,000 epinephrine (n = 13), or neither (plain, n = 3). The requirements of sedatives (diazepam, thiamylal) and analgesic (butorphanol) prior to the second epidural injection were compared among the four groups. The dose of intravenous diazepam or thiamylal required for sedation in the patients receiving lidocaine with 1:100,000 clonidine had a tendency to be smaller as compared with those in other three groups. There was a significant difference (P < 0.05) in the requirement of diazepam between the patients given lidocaine with 1:100,000 clonidine and those given plain lidocaine. The present results suggest that the addition of clonidine to lidocaine solution could reduce the requirements of sedatives in epidural anesthesia.