Gabapentin may improve sexual function in women with vulvodynia

Reference

Bachmann GA, Brown CS, Phillips NA, et al, for the Gabapentin Study Group. Effect of gabapentin on sexual function in vulvodynia: a randomized, placebo-controlled trial. Am J Obstet Gynecol 2019;220:89e1-89e8.

Synopsis

Vulvodynia is a chronic pain condition that affects female sexual function across all domains, as measured by the FSFI (range = 2 to 36, where higher scores mean better quality of life). The best characterized and most common subset of vulvodynia is provoked vulvodynia (PVD) localized to the vestibule (immediately anterior to the hymenal ring). PVD occurs only on contact, such as with penetration of a tampon or with sexual intercourse. The authors conducted a randomized placebo-controlled crossover trial of gabapentin versus placebo among women (N = 89) with a history of vulvodynia and PVD as measured by the application of standardized digital force. Pain was measured using an 11-point numeric scale—0 (none) to 10 (worst)—at baseline and at the conclusion of each phase of treatment. Women were allocated to receive both gabapentin and placebo in two 6-week phases, with randomized sequencing. Analysis was by intention to treat, with 66 women completing treatment. Treatment was titrated to the maximum tolerated dose over the first 4 weeks of each phase to a maximum of 3600 mg gabapentin (mean 2476 +/- 866 mg). The FSFI score at the completion of the gabapentin phase versus the placebo phase of the trial was a mean 1.3 points better (95% CI 0.4 - 2.2; P = .008). Although statistically significant, the clinical significance is minimal.There were significant improvements in 3 of the individual FSFI domains (sexual desire, arousal, and satisfaction), but not in the other 3 (orgasm, lubrication, or pain). Pain with the standardized digital force assessment at the conclusion of the active treatment phase was statistically improved after the placebo phase among women with an initial assessment of PVD of at least 5 (mean difference 1.6; 0.3 - 2.8), but not among women with scores of 4 or less. Side effects (none serious) with gabapentin were more frequent than with placebo, though none reached statistical significance: rhinitis (11.2% vs 4.5%), dizziness (10.1 % vs 3.4%), headache (7.9% vs 5.6%), and fatigue (5.6% vs 1.1%). Final FSFI scores did not approach the scores of untreated healthy control patients.