Objective: To compare the effectiveness and tolerability of gabapentin with placebo for the treatment of hot flashes in women who enter menopause naturally.
Design: A randomized, double-blind, placebo-controlled trial was conducted across the greater Toronto area between March 2004 and April 2006 in the community and primary care settings. Eligible participants were 200 women in natural menopause, aged 45 to 65 years, having at least 14 hot flashes per week. Study participants were randomized to receive gabapentin 300 mg oral capsules or placebo three times daily for 4 weeks. The primary outcome measure was the mean percentage change from baseline to week 4 in daily hot flash score, determined from participant diaries. Secondary outcome measures included changes in weekly mean hot flash scores and frequencies, quality of life, and adverse events.
Results: Of the 197 participants, 193 (98%) completed the study. Analysis was by intention to treat. Hot flash scores decreased by 51% (95% CI: 43%-58%) in the gabapentin group, compared with 26% (95% CI: 18%-35%) on placebo, from baseline to week 4. This twofold improvement was statistically significant (P < 0.001). The Menopause-Specific Quality-of-Life vasomotor score decreased by 1.7 (95% CI: 1.3-2.1; P < 0.001) in the gabapentin group. These women reported greater dizziness (18%), unsteadiness (14%), and drowsiness (12%) at week 1 compared with those taking placebo; however, these symptoms improved by week 2 and returned to baseline levels by week 4.
Conclusions: Gabapentin at 900 mg/day is an effective and well-tolerated treatment for hot flashes.
From the 1The Scarborough Hospital, Department of Family and Community Medicine, University of Toronto, Toronto, Ontario; 2Department of Radiation Oncology, University of Western Ontario, London, Ontario; 3Department of Family Medicine, University of Calgary, Calgary, Alberta; 4Departments of Obstetrics and Gynaecology, Family Medicine, and Community Health Sciences, University of Calgary, Calgary, Alberta; and 5Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada.
Received February 28, 2007; revised and accepted May 7, 2007.
Funding/support: This study was funded by the Physicians' Services Incorporated Foundation (grant 03-19) and the University of Toronto, Faculty of Medicine Dean's Fund (New Staff Grant). The gabapentin capsules were donated by Pfizer Inc. Neither funding source nor Pfizer had any role in study design; collection, analysis, or interpretation of data; or the writing of this report.
Trial Registration: clinicaltrials.gov. Identifier: NCT00112138.
Financial disclosure: None reported.
Address correspondence to: Debra Butt, MSc, MD, CCFP, The Scarborough Hospital Urban Outreach Health Centre, 3000 Lawrence Avenue East, Bldg A, Second Floor, Scarborough, Ontario, Canada M1P 2V1. E-mail: firstname.lastname@example.org