The dose-response relationship for clonidine added to a postoperative continuous epidural infusion of ropivacaine in children

Epidurally administered clonidine enhances the quality and duration of post operative analgesia when it is used as an adjunct to local anesthetics in c hildren. We investigated the dose-response relationship for epidural clonid ine when added to a continuous postoperative epidural infusion of ropivacai ne. By use of an observer-blinded design, 55 pediatric patients (1-4 yr old ) were randomly given a postoperative epidural infusion of plain ropivacain e 0.1% 0.2 mg.kg(-1).h(-1) (Group R), ropivacaine 0.08% 0.16 mg.kg(-1).h(-1 ) plus clonidine 0.04 mug.kg(-1).h(-1) (Group RC1), ropivacaine 0.08% 0.16 mg.kg(-1).h(-1) plus clonidine 0.08 mug.kg(-1).h(-1) (Group RC2), or ropiva caine 0.08% 0.16 mg.kg(-1).h(-1) plus clonidine 0.12 mug.kg(-1).h(-1) (Grou p RC3). A clear dose-response relationship could be identified for a contin uous infusion of epidural clonidine, with clonidine dosages in the 0.08-0.1 2 mug.kg(-1).h(-1) range providing improved postoperative analgesia (reduce d Children's Hospital of Eastern Ontario pain score, increased time to firs t supplemental analgesic demand, and a reduced total number of doses of sup plemental analgesics during the first 48 h after surgery). Analgesia was im proved without any signs of increased sedation or other side effects. The a djunct use of epidural clonidine in the dosage range of 0.08-0.12 mug.kg(-1 ).h(-1) appears effective and safe for use in children.