The efficacy and safety of low dose epidural butorphanol on postoperative analgesia following cesarean delivery.

Butorphanol is considered an effective and safe analgesic after cesarean delivery but is associated with profound dose-dependent sedation. Somnolence may cause hindrance in early mother-baby interaction. This study was designed to assess the analgesic efficacy and to monitor side-effects of low doses (0.5 mg and 0.75 mg) of epidural butorphanol with bupivacaine compared to bupivacaine alone in parturients following cesarean delivery. One hundred and twenty parturients (American Society of Anesthesiologists physical status 1 and 2) undergoing cesarean delivery were allocated into three groups: group 1 received epidural 0.125% bupivacaine while group 2 and 3 received an additional 0.5 mg and 0.75 mg butorphanol respectively. A combined spinal, epidural technique was used. Spinal anaesthesia was used for surgery. The epidural route was used for postoperative analgesia with the study drug. Onset, duration and quality of analgesia, lowest visual analogue scales (VAS) score, and side effects were noted. The onset and duration of analgesia in group 2 (4.1+/-2.6 min and 202.4+/-62.8 min) and group 3 (4.0+/-2.5 min and 192.3+/-69.1 min) were significantly different (P<0.01) from group 1 (6.6+/-2.7 min and 145.7+/-89.6 min). The quality of analgesia in terms of time to first independent movement and satisfactory VAS were statistically better (P<0.01) in group 2 (3.9+/-0.3 hour and 8.1+/-0.1 mm) and group 3 (3.8+/-0.4 hour and 8.1+/-0.9 mm) than in group 1 (5.2+/-0.4 hour and 6.3+/-1.3 mm). The incidence of sedation was 5% in all the three groups. A lower dose of epidural butorphanol with bupivacaine produces a significantly earlier onset, longer duration and better quality of analgesia than bupivacaine does.