Epidural fentanyl and perineal pain in labour.

Perineal pain during the course of routine epidural analgesia with bupivacaine was treated with a 10-ml top-up of either bupivacaine 25 mg, fentanyl 100 micrograms or fentanyl 100 micrograms plus bupivacaine 10 mg, in 46 women in the first stage of labour. Only fentanyl plus bupivacaine produced consistently reliable analgesia which was quicker in onset and longer in duration (140, SD 26 minutes) than either fentanyl (114, SD 26 minutes) or bupivacaine (99, SD 44 minutes) alone. Side effects, itching and drowsiness, which were not troublesome, were more frequent in the groups given fentanyl.