The effect of adding a minidose of clonidine to intrathecal sufentanil for labor analgesia

Background: Preliminary studies have suggested that the addition of clonidine to intrathecal sufentanil prolongs analgesia without producing motor blockade. Methods: Fifty-three nulliparous women in painful labor were included in this prospective, randomized, double-blinded study. Parturients at 2- to 5-cm cervical dilation received either 5 mu g sufentanil plus 30 mu g clonidine or 5 mu g sufentanil intrathecally, followed by 5 mg bupivacaine epidurally. The primary outcome was time until first request for additional analgesia. Visual analog pain scores, sensory changes, blood pressure, heart rate, ephedrine requirements, motor blockade, sedation, pruritus, and nausea were also recorded. Results: All parturients but one had effective analgesia in both groups, with similar sensory levels never exceeding T2. The duration (mean +/- SD) of analgesia was longer in the sufentanil-clonidine group: 125 +/- 46 versus 97 +/- 30 min(P = 0.007). The incidence of hypotension and the ephedrine requirements (median with range) were higher in the sufentanil-clonidine group: 63% versus 12% (P < 0.001) and 7.5 mg [range, 0-25.5 mg] versus 0 mg [range, 0-6 mg] (P < 0.0001). The incidence of fetal heart rate abnormalities during the first 30 min after intrathecal injection was similar in both groups (17% vs. 13%). No parturient had motor blockade. Conclusions: The addition of 30 mu g clonidine to 5 mu g intrathecal sufentanil extended the duration of labor analgesia without producing motor blockade. However, as previously reported with 100-200 mu g clonidine, the incidence of hypotension and the ephedrine requirements were also increased, even when 30 mu g clonidine only was added.