Gabapentin 'Effective' for Treatment of Anxiety in Breast Cancer Survivors
“At both the 300 and 900 mg doses, significant reductions in anxiety were seen at 4 and 8 weeks,” reported lead author Jill E. Lavigne, PhD, MS, MPH, of the Wegmans School of Pharmacy, St. John Fisher College in Rochester, NY, and coauthors.
Gabapentin is used to treat neuropathic pain and hot flashes in breast cancer survivors. Despite scant clinical trial data, it is also frequently prescribed, off-label, to treat their anxiety.
The authors conducted a randomized, double-blinded, controlled trial of 420 breast cancer patients who had completed chemotherapy. Anxiety and pain measures were taken at baseline, and at 4 and 8 weeks after baseline.
At 4 weeks, patients in the gabapentin 300-mg arm of the study saw significant improvements in anxiety scores, compared to placebo (P=0.005) – gains that were found to persist at 8 weeks (P<0.005), the authors noted. Anxiety worsened over the same period for patients in the placebo arm.
“Notably, the lower, 300 mg dose was associated with the best treatment outcomes for all patients except those with the highest baseline anxiety,” the authors noted. “This may be due to increased side effects at the higher gabapentin dose (900 mg).” Established common side effects for gabapentin include drowsiness, cold symptoms, weakness, blurred vision, dementia and delusions, the authors reported.
At higher doses (1,800 mg/day), gabapentin is used for adjuvant treatment of cancer pain, but pain scores in this clinical study population were low and did not appear to underlie declines in anxiety associated with the study's much lower 300-mg and 900-mg dose regimens, the authors reported.
The authors declared that they have no conflicts of interest. Pfizer provided gabapentin and placebo for the study, which was funded by the National Cancer Institute (NCI).