Gabapentin has Longer-Term Efficacy for the Treatment of Chronic Pelvic Pain in Women: A Systematic Review and Pilot Meta-analysis

Introduction Gabapentin has potential analgesic benefits in patients with neuropathic pain, such as post-herpetic neuralgia and diabetic peripheral neuropathy neuropathic pain. However, its efficacy in women with chronic pelvic pain (CPP) remains contradictory. In the present study, we performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to ascertain the efficacy of this treatment. Methods We systematically reviewed RCTs published in PubMed, Embase, the Cochrane Library, Web of Science, and Google Scholar databases, up to July 2021. These articles compared gabapentin with placebo or any other active treatment for CPP in women, with 'the change in pain scores from the baseline during the first 3 and 6 months of treatment' taken as the primary outcome. We considered reductions equivalent to 1.0 cm for primary outcomes to be clinically important. Results Four studies, comprising 469 participants, were included in our meta-analysis. Results revealed that the gabapentin group had significantly higher change in pain intensity scores from baseline to 3 months [weighted mean difference (WMD) - 0.61 cm; 95% confidence interval (CI) - 0.97 to - 0.25; I-2 = 0%; p = 0.0009] and 6 months (WMD - 1.38 cm; 95% CI - 1.89 to - 0.88; I-2 = 0%; p < 0.00001), relative to the control group. The difference of 6-month pooled result was more clinically important. Results from analysis of secondary outcomes showed that gabapentin had no beneficial efficacy during the first 3 months of treatment. Although gabapentin treatment was associated with a higher risk of dizziness and somnolence, no statistically significant differences were observed with regards to the total incidence of adverse events. Conclusions Overall, gabapentin could be a potential treatment option for CPP in women. However, as a pilot study, further studies are needed to explore the longer-term benefits and definite safety of this therapy in the future. Registration Number PROSPERO registration number CRD42021249421.