Use of gabapentin for perioperative pain control -- a meta-analysis

Abstract

Background: Gabapentin, an anticonvulsant, has recently been suggested as an effective postoperative 'analgesic' agent. The objective of the present study was to examine the analgesic effectiveness, opioid-sparing effects and side effects associated with the use of gabapentin in a perioperative setting.

Methods: Following the Quality of Reporting of Meta-analyses recommendations, nine electronic databases until February 2006 were searched, without language restriction, for randomized controlled trials comparing gabapentin with control for postoperative pain control. Outcome measures, namely, 24 h cumulative opioid consumption, visual analogue scale pain scores and adverse effects, were expressed as odds ratios, ratio of means or weighted mean differences (as appropriate), which were aggregated under the fixed or random effects models.

Results: Gabapentin caused a 35% reduction in total opioid consumption over the first 24 h following surgery (ratio of means 0.65, 95% CI 0.59 to 0.72), a significant reduction in postoperative pain at rest (in the first 24 h) and with movement (at 2 h, 4 h and 12 h), regardless of whether treatment effects were expressed as ratios of means or weighted mean differences, and a reduction of vomiting (relative risk [RR] 0.73, 95% CI 0.56 to 0.95) and pruritus (RR 0.30, 95% CI 0.13 to 0.70). It was associated with a significant increase in dizziness (RR 1.40, 95% CI 1.06 to 1.84) and an increase in sedation of borderline significance (RR 1.65, 95% CI 1.00 to 2.74).

Conclusion: Gabapentin improves the analgesic efficacy of opioids both at rest and with movement, reduces analgesic consumption and opioid-related adverse effects, but is associated with an increased incidence of sedation and dizziness.

Figure 1)

Meta-analysis flow diagram

Figure 2)

Per cent reduction in visual analogue scale (VAS) pain scores at rest with gabapentin over the first 24 h following surgery. The closed circles are the point estimates for pooled treatment effects, expressed as ratios of means (random effects model) at 2 h, 4 h, 12 h and 24 h following surgery. The error bars are the corresponding 95% CIs. The table below the graph reports the heterogeneity (I² statistic) for these treatment effects. The text adjacent to each point estimate is the same treatment effect expressed as the absolute reduction in VAS scores (weighted mean difference in random effects model) with 95% CI

Figure 3)

Per cent reduction in visual analogue scale (VAS) pain scores with movement by gabapentin over the first 24 h following surgery. The closed circles are the point estimates for pooled treatment effects, expressed as ratios of means (random effects model) at 2 h, 4 h, 12 h and 24 h following surgery. The error bars are the corresponding 95% CIs. The table below the graph reports the heterogeneity (I² statistic) for these treatment effects. The text adjacent to each point estimate is the same treatment effect expressed as the absolute reduction in VAS scores (weighted mean difference in random effects model) with 95% CI