A single preoperative dose of gabapentin does not improve postcesarean delivery pain management: a randomized, double-blind, placebo-controlled dose-finding trial.

BACKGROUND: A single preoperative dose of 600 mg gabapentin, combined with multimodal analgesia, has previously been shown to reduce postcesarean pain and improve maternal satisfaction but was associated with increased maternal sedation. We hypothesized that a lower dose of gabapentin may be effective with less sedation.

METHODS: We conducted a doubleblind, randomized, placebo-controlled study. Women undergoing elective cesarean delivery were randomized into 3 groups to receive 300 or 600 mg oral gabapentin, or placebo, 1 hour before surgery. Temporal summation (TS) testing was performed at the time of study drug administration, and a visual analog scale (0 to 100 mm) difference ≥10 mm between the 1st and 10th stimuli was considered TS+. Spinal anesthesia and postoperative analgesia were instituted, including intrathecal fentanyl and morphine, oral diclofenac and acetaminophen, and systemic morphine as required. Pain assessments at rest and on movement (visual analog scale 0 to 100 mm) were conducted at 6, 12, 24, and 48 hours after surgical incision. The primary outcome was pain on movement at 24 hours. Secondary outcomes included satisfaction with analgesia, supplemental opioid consumption, lactation difficulties, neonatal outcomes, maternal sedation, and other adverse effects. Three months after delivery, patients were contacted for assessment of chronic pain.

RESULTS: One hundred thirty-two women were randomized and 6 were excluded. The difference in mean pain scores at 24 hours (95% confidence intervals [CI]) were as follows: 600 mg versus 300 mg mean difference: 5 mm (95% adjusted CI, -7 to 17); 600 mg versus placebo: 3 mm (-9 to 15); 300 mg versus placebo: -2 mm [-14 to 10]; overall P value = 0.61. There was no apparent benefit of gabapentin in TS+ women, although overall pain scores were significantly higher in these women irrespective of the study group.

CONCLUSION: Given the wide confidence intervals of the differences in mean pain scores, the current study did not allow us to determine whether a single preoperative dose of gabapentin (300 mg and 600 mg) improved postcesarean analgesia compared to placebo in the context of a multimodal analgesic regimen. A larger study is required.