BACKGROUND AND PURPOSE: 

• A few previous RCTs that assessed the use of gabapentin to treat vulvodynia did not show benefit; however, studies had design limitations  
• Despite lack of evidence, gabapentin is in use for this indication and appears in some guidelines on this topic   
• Brown et al. (Obstetrics & Gynecology 2018) sought to determine the efficacy of extended-release gabapentin in the treatment of localized provoked vulvodynia (previously known as vulvar vestibulitis) 

METHODS: 

• Multicenter double-blind, placebo-controlled randomized crossover trial (RCT) 
• Participants
  • 18-50 years (later extended to >50) 
  • 3 continuous mounts of insertional dyspareunia  
  • Pain to vulvar touch and/or tampon insertion during pelvic exam  
• Patients received either
  • Gabapentin (1,200-3,000 mg/d)  
  • Placebo 
• 8 phase protocol  
  • 2-week screening phase | randomization | 4-week dose titration | 2-week maintenance phase | 2-week dose taper | 4-week dose titration after crossover | 2-week postcrossover maintenance | 2-week dose taper phase with scheduled visits at 6, 8, 14, and 16 weeks 
• Tampon pain test 
  • Validated 11-point numeric rating scale ranging from 0 (no pain) to 10 (worst pain) 
• Sexual intercourse and daily pain were also recorded on an 11 point (0-10) numeric rating scale  
• Primary outcome:  
  • Mean pain intensity on the tampon test (tampon insertion and removal test used as a surrogate marker for dyspareunia) during the last 7 days of the maintenance phase  
• Secondary outcomes  
  • Sexual intercourse pain and daily pain

RESULTS: 

• 89 women participants were randomized  
• There was no difference in tampon test pain with gabapentin vs placebo (P=.07) 
  • Adjusted mean 4.0 vs 4.3; difference −0.3 (95% CI −0.7 to 0.0) 
• Similarly, there was no improvement with gabapentin vs placebo for  
  • Sexual intercourse pain (P=.76)  
  • Daily pain (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: 

• Gabapentin did not reduce tampon test pain, compared to placebo 
• The authors state  

Because previous RCTs studying pharmacologic management options also have been negative, practitioners may want to consider all therapeutic options, including nonpharmacologic management interventions such as physical therapy and behavioral and sexual counseling. 

Learn More – Primary Sources: 

Gabapentin for the Treatment of Vulvodynia: A Randomized Controlled Trial 

Related ObG Topics:

Evaluating Vulvodynia – Making the Diagnosis and Key Points

Is Catechol-O-Methyltransferase a Cause of Pain in Vulvodynia?

Pelvic Floor Physical Therapy – PFPT and When to Use it