Small-Dose Intrathecal Clonidine and Isobaric Bupivacaine for Orthopedic Surgery: A Dose-Response Study

Abstract

We examined the dose-response relationship of intrathecal clonidine at small doses (<or=150 microg) with respect to prolonging bupivacaine spinal anesthesia. We aimed for establishing doses of intrathecal clonidine that would produce clinically relevant prolongation of spinal anesthesia and pain relief without significant side effects. Eighty orthopedic patients were randomly assigned to intrathecally receive isobaric 0.5% bupivacaine, 18 mg, plus saline (Group 1), clonidine 37.5 microg (Group 2), clonidine 75 microg (Group 3), and clonidine 150 microg (Group 4). Duration of the sensory block (regression below level L1) was increased in patients receiving intrathecal clonidine: 288 +/- 62 min (Group 1, control), 311 +/- 101 min in Group 2 (+8%), 325 +/- 69 min in Group 3 (+13%), and 337 +/- 78 min in Group 4 (+17%) (estimated parameter for dose 0.23 [95% confidence interval -0.05-0.50]). Duration of pain relief from intrathecal clonidine administration until the first request for supplemental analgesia was significantly prolonged: 295 +/- 80 min (Group 1, control), 343 +/- 75 min in Group 2 (+16%), 381 +/- 117 min in Group 3 (+29%), and 445 +/- 136 min in Group 4 (+51%) (estimated parameter for dose 1.02 [95% confidence interval 0.59-1.45]). Relative hemodynamic stability was maintained and there were no between-group differences in the sedation score. We conclude that small doses of intrathecal clonidine (<or=150 microg) significantly prolong the anesthetic and analgesic effects of bupivacaine in a dose-dependent manner and that 150 microg of clonidine seems to be the preferred dose, in terms of effect versus unwarranted side effects, when prolongation of spinal anesthesia is desired.

Clinical efficacy of clonidine versus nalbuphine as intrathecal adjuvants to 0.5% hyperbaric bupivacaine for subarachnoid block during gynaecological procedures: a double blind study

“…Similar results were also observed by Strebel et al and Gecaj-Gashi et al . 10,11 This was also in accordance to the study of Tilker et al who also reported that the time taken for regression of sensory block was statistically more in patients of clonidine group. 12 Gupta K et al compared the analgesic efficacy of intrathecal clonidine, 30 µg with butorphanol 0.20 mg during orthopedic surgeries.…”

ntrathecal Hyperbaric Bupivacaine with Two Different Doses of Clonidine in Lower Limb Orthopaedic Surgery: A Comparative Study

“…readings remained above the critical value of 65 mmHg at majority of times. These findings agree with other investigators demonstrating a decrease in arterial BP even with lower doses (15-150 g) of clonidine and relative hemodynamic stability with administration of larger doses [5,6,8,20,24] . Some authors argued that the hypotensive effects of clonidine at lower dose can be because of low dose of Bupivacaine used in those studies.…”

“…VAS scores were significantly lesser with combination (BC-150<BC-75< B). Our study results were similar to Baker [19] , Strebel et al [20] , Grandhe [15] , Sethi et al [1] , Filos KS (1994) [21] , Mercier F J (1998) [22] and Chiari et al (1999) [23] .…”

Effect of Clonidine and/or Fentanyl in Combination with Intrathecal Bupivacaine for Lower Limb Orthopedic Surgeries in Spinal Anaesthesia

“…Grace et al, however observed prolonged time to onset of motor block in pethidine-clonidine group which is in contrast to the results of our study. 25 The difference in the result could be due to the fact that higher doses of pethidine 0.75 mg/kg was used in this study. It is possible that the higher dose of intrathecal pethidine could mask the effect of intrathecal clonidine.…”