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 300mg gabapentin versus 900mg 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 weeks and 8 weeks. Pain was measured at baseline using a 10-point scale. Analyses included analysis of covariance (ANCOVA) and ordinary least squares regression.
At 4 weeks, state anxiety change scores were significantly better for gabapentin 300mg and 900mg (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 < 0.005). We found no significant interactions.
Given its similar pharmacology, efficacy in the treatment of hot flashes, and low cost, gabapentin may provide a low cost and parsimonious alternative treatment choice for breast cancer survivors presenting in primary care practices with anxiety symptoms. Gabapentin is effective for hot flashes, and therefore may provide therapeutic benefit for both anxiety and hot flashes at a generic drug price. For patients reluctant to take a controlled substance, such as a benzodiazepine, gabapentin may offer an alternative therapy. Similarly, patients with a history of substance use may benefit from gabapentin without risk of addiction or abuse.
For cancer survivors experiencing both hot flashes and anxiety, gabapentin may provide a single effective treatment for both and is an alternative therapy for anxiety for patients unwilling to take a benzodiazepine or those with a history of substance use.