Does gabapentin have an analgesic effect on background, movement and referred pain? A randomised, double-blind, placebo controlled study

Aim: To establish the effect of oral gabapentin on background, movement and referred pain in human subjects. Method: A randomised, double-blind, placebo controlled study of 80 adult patients with low back pain and associated referred leg pain. Baseline pain scores were measured; active treatment was with a dose of gabapentin increasing to 1200 mg daily over a six week period, the placebo group receiving an equal number of inactive capsules. 0-10 numerical pain scores were recorded daily throughout the study period (background, movement and referred pain), along with a measure of mobility and concomitant analgesic consumption. Results: 65 subjects provided results. There was no change in pain scores from baseline recordings to week 8 in terms of background pain. Gabapentin reduced referred pain by 0.45 after 8 weeks (p < 0.05) and movement pain by 0.47 (p < 0.05). There were no changes in mobility scores and analgesic consumption was only marginally reduced by use of gabapentin (0.45 tablets per day, p = 0.05). Conclusion: Gabapentin in a dose increasing to 1200 mg per day has no effect on background pain and only a marginal effect on referred pain and pain on movement.