Biglia, N., Sgandurra, P., Peano, E., Marenco, D., Moggio, G., Bounous, V., … Sismondi, P. (2009). Non-hormonal treatment of hot flushes in breast cancer survivors: Gabapentin vs. vitamin E. Climacteric, 12, 310–318. 

The study assessed the efficacy and the tolerability of gabapentin 900 mg/day compared to vitamin E for the control of vasomotor symptoms in women with breast cancer.

Vitamin E was chosen as a placebo-equivalent on the basis of previous experience  showing only minimal effect on hot flushes in breast cancer participants, and no toxicity or side-effects. Participants were randomly allocated to one of two treatment groups: vitamin E 800 IU/day or gabapentin 900 mg/day by oral route (Neurontin 300 mg capsules) for a period of 12 weeks.

The sample was comprised of 115 postmenopausal women with a median age of 50 years. 

• Inclusion criteria:
  • Breast cancer surgically treated at least one year prior; no evidence of systemic disease 
  • Eight or more hot flushes per day 
  • Postmenopausal status (amenorrhea for more than 12 months or amenorrhea for 6–12 months with a serum FSH level greater than 40 mIU/ml and estradiol less than 20 pg/ml or bilateral oophorectomy or ovarian suppression by GnRH analogs) 
  • Adjuvant therapy with tamoxifen, aromatase inhibitors or GnRH analogs, provided that it was started at least two months before
• Exclusion criteria:
  • Use of any antidepressant treatment, progestagens, or any other medication to treat hot flushes within the previous three months 
  • Concomitant chemotherap
  •  Uncontrolled hypertension 
  • Impaired renal or hepatic function
  • Diabetes

This was a randomized, non-placebo-controlled, nonblinded study.

Each participant completed a one-week self-report diary on hot flushes at study entry and daily during the 12 weeks of study. In order to assess the duration of treatment efficacy, participants filled out the hot flush diary for three months after treatment discontinuation.

Treatment efficacy was assessed by two measures: frequency (total number of hot flushes) and severity score, calculated by assigning scores of 1, 2, 3 and 4, respectively, to mild, moderate, severe, and very severe hot flushes. This hot flush diary had previously been validated. Each value was obtained by averaging data collected over 1 week. Differences and percentage changes from baseline to weeks 4, 8, and 12 were calculated. Among the women allocated to vitamin E, 16.36% never started therapy, and 34.78% dropped out because of inefficacy. Hot flush frequency and score decreased by 57.05% and 66.87%, respectively (p = 50.05) in the gabapentin group. The effect of vitamin E was fairly small: hot flush frequency and severity score were reduced by 10.02% and 7.28%, respectively (p > 0.05).

Gabapentin 900 mg/day is effective for relieving hot flushes in participants previously treated for breast cancer. Vitamin E has only marginal effect on vasomotor symptoms.

Study limitations were small sample size and high dropout rate.