Baclofen Vaginal Suppositories in Chronic Pelvic Pain: a Randomized, Double-Blind, Placebo Controlled Trial

Why clinicians should know about it

• Picked for Anesthesiology and Pain Medicine (paper of the day, 6 November 2026): Placebo-controlled trial tests treatment for chronic pelvic pain

Abstract

BACKGROUND: Pelvic floor muscle dysfunction is a common contributor to chronic pelvic pain (CPP), yet targeted treatment options remain limited. OBJECTIVE: To determine whether baclofen vaginal suppositories in CPP is safe and effective when compared with placebo. METHODS: This randomized, double-blind, placebo-controlled trial compared 20mg baclofen vaginal suppositories to placebo suppositories nightly in women with CPP. Women older than18 years without allergy to baclofen or the suppository base were included if they had ≥40/100 mm pain on a visual analogue scale (VAS) with palpation of the obturator internus or levator ani on standardized pelvic exam. Improvement in this standardized pelvic exam 100mm VAS pain score represented the primary outcome. Participants completed Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference, PROMIS global health, PROMIS sexual function at baseline, 4, and 8 weeks, with repeat pelvic examination at 8 weeks. The study was powered to detect the minimum clinically important difference (MCID) of 20mm on a 100mm VAS pain scale on a standardized pelvic floor muscle examination with a total sample size of 34, 17 in each group. Adverse events, pill count, and other treatments for CPP during the study period were collected. Differences between treatment groups were assessed using the Mann-Whitney test, and multiple imputation was used to account for missing data. RESULTS: A total of 39 women were enrolled in the study with 37 randomized.19 patients received baclofen vaginal suppositories and 18 received placebo suppositories. Demographic data was similar between groups, with similar mean age (42.5 ± 12.5 baclofen vs 46.3 ± 12.2 placebo) and body mass index (29.4 ± 6.7 vs 29.8 ± 7.6). There was a statistically and clinically significant improvement in the primary outcome of change in the 100mm VAS pain score on pelvic floor muscle examination at 8 weeks relative to baseline in the baclofen group as compared to placebo (median improvement of 33.5 mm [IQR: 30 to 46.230.0] baclofen vs 7.2 mm [0.0 to 10.0] placebo, p=<0.001). Further, patient-reported overall 100mm VAS pain was also significantly improved with baclofen when compared to placebo (median improvement 32.0 mm [14.0 to 43.0] baclofen vs 0.0 mm [-6.5 to 11.8] placebo, p=0.001) (Figure 2). Other validated questionnaires demonstrated no significant differences between baclofen and placebo. Medication compliance, assessed using Spearman correlation between the number of missed doses and the survey score at 8 weeks, did not impact the outcomes among those in the baclofen arm. There were no adverse events in the baclofen group. In the placebo group one participant had intermittent headaches and one participant had irritated vaginal skin. CONCLUSIONS: In this appropriately powered, randomized trial, patients experienced statistically and clinically significantly less pain with 8 weeks of nightly baclofen vaginal suppositories when compared to placebo. Baclofen suppositories were shown to be well tolerated with no adverse events.

Abstract as published, via PubMed.