Gabapentin for the treatment of carpal tunnel syndrome: a randomized controlled trial.

OBJECTIVE: Based on its efficacy in treating neuropathic pain, gabapentin may be effective for the treatment of carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the efficacy of gabapentin for symptom relief in CTS.

METHODS: We conducted a randomized, double-blinded, placebo-controlled trial recruiting patients with newly diagnosed idiopathic CTS of more than a period of three months. Diagnosis was based on characteristic symptoms with electrophysiological confirmation. Patients were randomly assigned to an active group receiving gabapentin (starting dose 300 mg once daily to a target of 900 mg daily) or a placebo group. Primary end-point was the global symptom score (GSS), which was measured at baseline, two, and eight weeks.

RESULTS: There was no significant difference in baseline variables between the two treatment groups. Hundred and forty patients were enrolled in the study, of whom 71 were randomly assigned to gabapentin group and 69 assigned to placebo group. Both gabapentin and placebo produced significant improvement in symptoms at two and eight weeks. The GSS at 2 and 8 weeks was 16.4 (SD 9.4) and 13.4 (SD 9.7), respectively, in the active group versus 14.9 (SD 9.0) and 12.5 (SD 8.9) in the control group (P < 0.01). But by eight weeks, the mean reduction in symptom severity of patients on gabapentin [-10.4 (SD 10.8)] was not significant when compared with placebo [-8.7 (SD 8.1), P < 0.39]. Adverse events were not severe and included dizziness, somnolence, and headache.

CONCLUSIONS: Gabapentin did not produce a significant reduction in symptom severity compared with placebo over an eight-week period.