Is Gabapentin Effective in Reducing Pain in Women with Chronic Pelvic Pain?

OBJECTIVE: The objective of this selective EBM review is to determine whether or not gabapentin is effective in reducing pain in women with chronic pelvic pain. STUDY DESIGN: A review of three randomized, placebo-controlled trials (RCTs) that were peer reviewed and published in English after 2016. DATA SOURCE: All articles were published in peer reviewed journals and were researched using PubMed, Alt HealthWatch, AMED, and CINAHL. Studies were selected based on their ability to answer the question posed in the objective, and if the researched outcomes were patient oriented. OUTCOMES: The assessed outcome is pelvic pain. It is measured by Visual Analog Scale (VAS) and Numerical Rating Scale (NRS). VAS is a subjective measure where a patient can mark their degree of pain on a visual scale, without numerical values. NRS is a subjective measure for patients where they are able to rate their pain on a scale of 1-10, with 10 being the worst pain. RESULTS: Lewis et al. found a mean change from baseline of 3.0 in the gabapentin group and 1.8 in the placebo group. The difference in means was 0.98 (CI 95%, -0.87 to +2.83, p= 0.28). Horne et al. found a mean change from baseline of -1.1 in the gabapentin group and -0.9 in the placebo group. The difference in means was -0.18 (CI 97.5%, -0.71 to + 0.35, p= 0.45). AbdelHafeez et al. found a NNT of 3, with a RR of 0.5 (95% CI, 0.34-0.75, p<0.001) in favor of gabapentin decreasing pain. This was the only study that found a significant reduction in pain with gabapentin compared to placebo. CONCLUSIONS: Uncertainty remains regarding gabapentin and its use. The results of these three studies showed that gabapentin may or may not be effective in reducing pain in women with chronic pelvic pain. There is a need for a large randomized, placebo-controlled trial for a definitive result.