A randomized, controlled, double-blinded clinical trial of gabapentin 300 versus 900 mg versus placebo for anxiety symptoms in breast cancer survivors

Gabapentin is used for the treatment of hot flashes and neuropathic pain in breast cancer survivors, and is commonly used off-label for the treatment of anxiety. Yet, clinical trial evidence to support the use of gabapentin for anxiety symptoms is lacking. In a randomized, double-blinded controlled trial we compared 300 mg gabapentin versus 900 mg gabapentin versus placebo. Subjects were 420 breast cancer patients who had completed all chemotherapy cycles. Anxiety traits and current (state) anxiety were measured using the Speilberger Strait-Trait Anxiety Inventory at baseline, 4 and 8 weeks. Pain was measured at baseline using a 10-point scale. Analyses included analysis of covariance and ordinary least squares regression. At 4 weeks, state anxiety change scores were significantly better for gabapentin 300 and 900 mg ( p = 0.005) compared to placebo. The magnitude of improvement was proportional to baseline state anxiety. At 8 weeks, the anxiolytic effects of gabapentin compared to placebo persisted ( p