An anti-seizure and nerve pain drug called gabapentin improved sexual function in women with chronic pain in the vulva (the external part of the female genitalia).
While the medication is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of fibromyalgia, some doctors prescribe it off-label.
The study, “Effect of gabapentin on sexual function in vulvodynia: a randomized, placebo-controlled trial,” was published in the American Journal of Obstetrics and Gynecology.
This is the first time scientists have evaluated gabapentin’s effects in women with vulva pain.
“Previous studies have suggested gabapentin reduces the pain of fibromyalgia, a chronic condition that includes widespread pain in various parts of the body,” Gloria Bachmann, MD, MMS, director of the Women’s Health Institute at Rutgers Robert Wood Johnson Medical School and the study’s first author, said in a press release.
During intercourse or insertion of a tampon, some women experience stinging, burning, irritation, or itching of the entry of the vagina, a condition known as provoked vulvodynia.
This chronic pain syndrome affects all domains of sexual function, including arousal, orgasm, satisfaction and pain.
Researchers previously reported that women with both vulvodynia and fibromyalgia have increased pelvic muscle pain as measured by a vaginal algometer — a device that measures the pressure pain threshold on the lateral walls of the vagina.
Bachmann’s team posited that “reducing pelvic floor muscle pain might reduce vulvodynia pain overall and thus improve sexual function.”
They set out to evaluate whether treatment with extended-release gabapentin improved sexual function in women with provoked vulvodynia and whether there was a relationship between treatment outcome and pelvic muscle pain severity.
The multi-center, placebo-controlled, double-blind control trial included 89 women (mean age 37) who complained of more than three continuous months of painful intercourse, pain upon vulvar touch, or vulvar pain with tampon insertion and during pelvic examination.
The study also included 56 pain-free control subjects. Both groups completed the Female Sexual Function Index scale at baseline and after six weeks of treatment with gabapentin and placebo.
Participants were randomly assigned to receive one of two treatment sequences: 1,200-3,000 mg/day gabapentin first and then placebo, or vice versa.
Compared with placebo, gabapentin significantly improved overall sexual function including desire, arousal, and satisfaction. Nonetheless, sexual function remained significantly lower than in the pain-free control participants, matched by age and race.
Additionally, “we found that women with greater muscle pain responded better in terms of pain and improved arousal than those with less pain, which suggests that gabapentin be considered for treatment in women who have significant muscle tightness and spasm in the pelvic region,” Bachmann said.