Twelve RCTs (n=896) were included.
All of the studies were of a high quality: all scored 6 or 7 out of 7 for the Cochrane Quality Score and 5 out of 5 on the Jadad scale.
Oral gabapentin was associated with a statistically significant reduction in post-operative pain at 20 to 24 hours (WMD -0.74, 95% CI: -1.03, -0.45) and at 0 to 4 hours (WMD -1.57, 95% CI: -2.14, -0.99) compared with the control. Forest plots showed significant heterogeneity (I2=79.6% and I2=89.6%, respectively).
Gabapentin was also associated with a statistically significant reduction in post-operative analgesic use (WMD -17.84, 95% CI: -23.50, -12.18) and a significantly increased incidence of sedation (WMD 3.28, 95% CI: 1.21, 8.87) compared with control.
There was no statistically significant difference between gabapentin and control in nausea, vomiting or dizziness/lightheadedness.
An estimated 119 studies (n=107,814) would be required to invalidate the findings of the meta-analysis.