Labor analgesia with intrathecal sufentanil has been shown to be prolonged by the addition of intrathecal clonidine. The current study was designed to determine if epidural clonidine would prolong labor analgesia provided by epidural sufentanil. Forty laboring primiparous women at less than 5 cm cervical dilation requesting epidural analgesia were enrolled. Following a 3 mt test dose of lidocaine with epinephrine, patients were randomized to receive 10 mt of either sufentanil 20 mu g (S) or sufentanil 20 mu g with clonidine 75 mu g (SC). After administration of the analgesic, pain scores and side-effects were recorded for each patient at 5, 10, 15, 20 and 30 min, and every 30 min thereafter, by an observer blinded to the technique used. There were no demographic differences between the two groups. Pain relief was rapid for all patients. The mean duration of analgesia was similar between the S group (153 +/- 78 min) and the SC group (178 +/- 55 min). Side-effects were similar between the two groups. There was no difference between the two groups in time from sufentanil administration to delivery, incidence of operative or assisted delivery, or cervical dilation at the time of redose. For early laboring patients, epidural sufentanil 20 mu g after a lidocaine test dose provides analgesia comparable to that of sufentanil 20 mu g with clonidine 75 mu g; there was no significant difference in analgesic duration between the two groups. (C) 2000 Harcourt Publishers Ltd.