Gabapentin for the Treatment of Vulvodynia: A Randomized Controlled Trial

• Published in: Obstetrics and gynecology (New York. 1953) Vol. 131; no. 6; pp. 1000 - 1007
• Main Authors: Brown, Candace S, Bachmann, Gloria A, Wan, Jim, Foster, David C
• Format: Journal Article
• Language: English
• Published: United States by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved 01.06.2018
• Subjects: Adult; Analgesics - administration & dosage; Cross-Over Studies; Delayed-Action Preparations; Diagnostic Techniques, Obstetrical and Gynecological; Double-Blind Method; Dyspareunia - drug therapy; Dyspareunia - psychology; Female; Gabapentin - administration & dosage; Humans; Middle Aged; Pain - drug therapy; Pain - etiology; Pain Measurement; Treatment Outcome; Vulvodynia - drug therapy; Vulvodynia - psychology
• ISSN: 0029-7844; 1873-233X
• DOI: 10.1097/AOG.0000000000002617

OBJECTIVE:To evaluate whether extended-release gabapentin is more effective than placebo among women with vulvodynia. METHODS: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. RESULTS:From August 2012 to January 2016, 230 women were screened at three academic institutions and 89 (mean age 37 years; 65% black) were randomized45 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. CONCLUSION: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. CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov, NCT01301001.