Conditions: Vulvodynia
Keywords: Vulvodynia
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 230
Healthy volunteers: yes

Brief summary:
The Specific aims of this project are to (1) test the prediction that pain from tampon insertion (primary outcome measure) is lower in PVD patients when treated with gabapentin compared to when treated with placebo. Secondary outcome measures include intercourse pain and 24-hour pain and (2)perform a mechanism-based analysis of gabapentin effectiveness, and to gain insight into the underlying pathophysiology of subtypes of PVD that may lead to more specific treatment options.

Detailed description:
This is a 18-week, randomized, double-blind, placebo-controlled, two-treatment, two-period crossover design, where 120 women between 18 of age and older who report insertional dyspareunia, pain with tampon insertion, and tenderness localized to the vulvar vestibule will be enrolled in the study. Electronically entered daily diaries will be used to determine if pain is lower in PVD subjects when treated with gabapentin (up to 3600 mg/d) compared to when treated with placebo. Biological measurements will include assessment of allodynia and hyperalgesia from capsaicin administration, muscle tension using a vaginal pressure algometer, number of tender points by clinical examination, and changes in blood pressure, pulse and heart rate variability. . The Long-range goals of this project are to explicate the underlying pathophysiologic mechanisms of PVD, and to use this knowledge to create evidence-based differential diagnoses of subtypes of PVD and to individualize treatments for each subtype. The immediate goal is to conduct a multicenter, randomized controlled trial (RCT) of gabapentin treatment for PVD, and which will also provide critical data on a new PVD-testing and response paradigm, as well as on characteristics that may define subtypes of PVD. Gabapentin, an anticonvulsant with analgesic, anxiolytic, and antispasmotic effects, was selected because of its efficacy in treating other neuropathic pain conditions.

Arms:
arm 1: Placebo capsule daily in first intervention period and Gabapentin capsule 3000 mg daily in in second intervention (after washout period) arm 2: Gabapentin capsule 3000 mg daily in first intervention period and Placebo capsule in second intervention (after washout period)

Interventions: intervention 1: Placebo oral capsule intervention 2: Gabapentin
Intervention descriptions: intervention 1: Placebo 2 capsules am and 3 capsules pm intervention 2: Gabapentin 1200 mg am and 1800 mg pm

Protocol document: