Clonidine effect on pain after cesarean delivery: A randomized controlled trial of different routes of administration

BACKGROUND: Intrathecal clonidine prolongs spinal anesthesia. We evaluated the effects of the addition of intrathecal or intravenous clonidine (75 µg) to standard cesarean delivery spinal anesthesia on postoperative pain and neonatal outcomes. METHODS: In a randomized, placebo-controlled, double-blind trial, 64 women scheduled for elective cesarean delivery under spinal anesthesia were randomly allocated and compared among 3 groups: intrathecal clonidine 75 µg, intravenous clonidine 75 µg, and placebo. The primary outcome was acute postoperative pain. A sample size of 26 individuals per group (N = 78) was planned. RESULTS: From April 2015 to April 2016, 64 women were analyzed (14 excluded). No differences in postoperative pain scores were found (Numerical Verbal Scale for pain at movement at 24 hours of postcesarean delivery: 4.53 ± 3.0 vs 4.45 ± 2.73 vs 3.93 ± 3.07 for control, intrathecal, and intravenous, respectively, P = .771). Intrathecal and intravenous clonidine led to more sedation, in comparison to the control group, during the intraoperative period (Richmond Agitation and Sedation Scale: -0.3 ± 0.47 vs -1 ± 0.53 vs -0.73 ± 0.45 for control, intrathecal, and intravenous, respectively, overall P < .001; Dunn correction: P < .001 for intrathecal versus control; P = .021 for intravenous versus control; and P = .208 for intrathecal versus intravenous). CONCLUSIONS: Intrathecal or intravenous clonidine had no effect on postoperative pain after cesarean delivery. Both intrathecal and intravenous clonidine caused more sedation.