Effect of epidural clonidine on minimum local anesthetic concentration (ED50) of levobupivacaine for caudal block in children

Paediatr Anaesth. 2011 Feb;21(2):128-35. doi: 10.1111/j.1460-9592.2010.03478.x. Epub 2010 Dec 16.


Background: Clonidine has the potential to significantly prolong the duration of caudal epidural anesthesia. We investigated the effect of the addition of clonidine to the MLAC of levobupivacaine in a randomized controlled dose-response trial.

Methods: A group of 120 children aged <6 years of age received caudal anesthesia with levobupivacaine and 1, 2, or 3 μg·kg(-1) of clonidine. The MLAC was determined according to a Dixon-Massey protocol. The primary outcome was effective surgical anesthesia. Secondary outcomes were the duration of postoperative analgesia, postoperative pain scores, clonidine side effects, and time to hospital discharge.

Results: The MLAC of caudal levobupivacaine was 0.106%, 0.077%, and 0.035% with 1, 2, and 3 μg·kg(-1) of clonidine, respectively. There were significant dose-dependent increases in median duration of analgesia. The incidence of delayed discharge, somnolence, and PONV was significantly increased in the 3 μg·kg(-1) of clonidine group.

Conclusions: Clonidine produces a local anesthetic sparing effect with a dose-dependent decrease in levobupivacaine MLAC for caudal anesthesia. In addition, there is a dose-dependent prolongation of postoperative analgesia following lower abdominal surgery in children. A dose of 2 μg·kg(-1) of clonidine provides the optimum balance between improved analgesia and minimal side effects.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adjuvants, Anesthesia*
  • Adrenergic alpha-Agonists / administration & dosage
  • Adrenergic alpha-Agonists / adverse effects
  • Adrenergic alpha-Agonists / pharmacology*
  • Analgesia, Epidural*
  • Anesthesia, Caudal / methods*
  • Anesthetics, Local / administration & dosage*
  • Anesthetics, Local / adverse effects
  • Anesthetics, Local / pharmacokinetics
  • Bupivacaine / administration & dosage
  • Bupivacaine / adverse effects
  • Bupivacaine / analogs & derivatives
  • Bupivacaine / pharmacokinetics
  • Child
  • Clonidine / administration & dosage
  • Clonidine / adverse effects
  • Clonidine / pharmacology*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Hernia, Inguinal
  • Humans
  • Levobupivacaine
  • Male
  • Orchiopexy
  • Postoperative Nausea and Vomiting / epidemiology
  • Preanesthetic Medication
  • Sample Size


  • Adjuvants, Anesthesia
  • Adrenergic alpha-Agonists
  • Anesthetics, Local
  • Levobupivacaine
  • Clonidine
  • Bupivacaine