The dose-sparing effect of clonidine added to ropivacaine for labor epidural analgesia.

Abstract

To determine the effects of clonidine with ropivacaine during epidural labor analgesia, we studied 66 nulliparous women in early active labor. Women were randomized to receive ropivacaine 0.1% 8 mL plus 75 microg of clonidine (Group 1), ropivacaine 0.2% 8 mL plus 0.5 mL of NaCl 0.9% (Group 2), or ropivacaine 0.2% 8 mL plus 75 microg of clonidine (Group 3) 5 min after a bupivacaine 7.5 mg with epinephrine 15 microg test dose. Upon request, additional analgesia with ropivacaine 0.1% 8 mL followed by ropivacaine 0.2% 8 mL/h was administered. With clonidine, duration of analgesia was increased (132 +/- 48 min [Group 1] and 154 +/- 42 min [Group 3] versus 91 +/- 44 min [Group 2]; P < 0.05), and total ropivacaine dose over the first 4 h was significantly reduced (40.5 +/- 15 mg [Group 1] and 47.0 +/- 16 mg [Group 3] versus 72.5 +/- 18 mg [Group 2]; P < 0.01). The incidence of more profound motor block was more frequent in Group 2 (P < 0.05). Although there was a trend for more women receiving clonidine to require ephedrine for treatment of hypotension, this did not seem to have an impact on fetal outcome or incidence of cesarean deliveries for nonreassuring fetal heart rate tracings. This study demonstrates the dose-sparing effect of clonidine when added to ropivacaine. The effect of adding 75 microg of clonidine to ropivacaine for epidural labor analgesia was studied. Clonidine increased analgesia duration and produced dose sparing compared with ropivacaine alone. Despite a tendency for hypotension in women receiving clonidine, there was no apparent effect on delivery mode or neonatal outcome.