Epidural fentanyl-bupivacaine compared with clonidine-bupivacaine for analgesia in labour.

Alpha-adrenergic agonists produce pain relief through an opioid independent mechanism and may be alternatives to opioids for combination with local anaesthetics for analgesia during labour. We studied 41 pregnant women. Epidural block was performed with 75 microg clonidine (n = 20) or 50 microg fentanyl (n = 21) combined with 0.125% bupivacaine (10 mL). Maternal vital parameters were measured. Analgesia was evaluated using a visual analogue scale (VAS); sedation was scored using a five-point scale. There were no differences in maternal vital parameters, fetal heart rate (FHR) or Apgar scores between the groups. Analgesia lasted longer in the bupivacaine-clonidine group (139.4 +/- 31 min) compared with the bupivacaine-fentanyl group (127.9 +/- 48 min) (P = 0.42). Additional analgesic requirement was more often in the fentanyl-bupivacaine group and total bupivacaine requirement was less in the clonidine-bupivacaine group (22.5 +/- 12.5 mg vs. 30.9 +/- 12.8 mg) (P = 0.04). This small study confirms that this combination of bupivacaine and clonidine provides satisfactory analgesia for first-stage labour, and of longer duration than bupivacaine-fentanyl.