To evaluate whether extended-release gabapentin is more effective than placebo among women with vulvodynia.
In a multicenter double-blind, placebo-controlled randomized crossover trial, gabapentin (1,200–3,000 mg/d) was compared with a placebo. The primary outcome was mean pain intensity (0, no pain at all to 10, worst pain ever) on the tampon test (a standardized tampon insertion and removal test used as a surrogate marker for dyspareunia) during the last 7 days of the maintenance phase. Secondary outcomes included sexual intercourse pain and daily pain. A sample size of 53 provided 90% power to detect a 1-point reduction on the tampon test (.05 level, two-sided) between the two treatment phases.
From August 2012 to January 2016, 230 women were screened at three academic institutions and 89 (mean age 37 years; 65% black) were randomized: 45 to gabapentin first and then placebo and 44 to placebo first and then gabapentin. Tampon test pain with gabapentin was not different compared with the placebo (adjusted mean 4.0, 95% CI 3.0–4.9 vs 4.3, 95% CI 3.4–5.2, difference −0.3, 95% CI −0.7 to 0.0; P=.07). Gabapentin also did not improve pain over placebo for sexual intercourse pain (adjusted mean 3.9, 95% CI 2.4–5.3 vs 4.0, 95% CI 2.5–5.4, difference −0.1, 95% CI −0.9 to 0.6; P=.76) and daily pain (adjusted mean 2.7, 95% CI 1.8–3.6 vs 2.9, 95% CI 2.0–3.8, difference −0.2, 95% CI −0.5 to −0.2; P=.36). Subset analyses found that longer pain duration and oral contraceptive nonuse were associated with minimal improvement in tampon test pain with gabapentin.
In this cohort, extended-release gabapentin, as compared with a placebo, did not reduce tampon test pain. These data do not support the recommendation of gabapentin alone as treatment for vulvodynia.
Women with vulvodynia do not report decreased vulvovaginal pain as measured by the tampon test after gabapentin intervention.
Departments of Clinical and Translational Science and Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; the Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey; and the Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, Rochester, New York.
Corresponding author: Candace S. Brown, PharmD, Department of Clinical Pharmacy and Translational Sciences, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163; email: email@example.com.
Supported by R01 HD065740 (to Dr. Brown) from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Office of Women's Health Research, and the University of Tennessee General Clinical Research Center. Depomed, Inc provided gabapentin extended release and a matching placebo, but was not involved in the concept or design of the clinical trial, did not have access to data for analysis or interpretation of the data, and did not contribute to writing of the manuscript.
Financial Disclosure The authors did not report any potential conflicts of interest.
Presented at the International Society of Vulvovaginal Disease World Congress, September 13–15, 2017, Mendoza, Argentina.
For a list of names in the GABA Study Group, please see Appendix 1, available online at http://links.lww.com/AOG/B94.
Each author has indicated that he or she has met the journal's requirements for authorship.