Efficacy and safety of Dysmenorrhea Patch acupoint application in women with primary dysmenorrhea: a randomized double-blind controlled trial

Background Primary dysmenorrhea (PD) is defined as pain occurring with menses in the absence of pelvic pathology. Traditional Chinese Medicine offers various therapeutic approaches for PD management. Dysmenorrhea Patch, an acupoint application therapy, shows promise for PD management, but its clinical efficacy and safety require further evaluation. This study aimed to assess the efficacy and safety of the Dysmenorrhea Patch in PD. Methods This multicenter, randomized, double-blind, placebo-controlled trial was conducted at outpatient clinics in Shanghai, China. Recruitment period: May 2021 through October 2024. Women aged 18–40 years with primary dysmenorrhea were randomized 1:1 to receive the Dysmenorrhea Patch (acupoint application patch) or a placebo patch for three consecutive menstrual cycles. Patches were applied to predefined acupoints for 8 hours daily during the non-menstrual phase of each cycle and withheld during menstruation. The primary endpoint was total effective rate (TER) based on the percentage reduction in Numerical Rating Scale (NRS) scores. Secondary endpoints included NRS, Cox Menstrual Symptom Scale (CMSS), Traditional Chinese Medicine (TCM) syndrome score, serum Prostaglandin F2α (PGF2α) and Prostaglandin E2 (PGE2), rescue ibuprofen use, and safety outcomes (local skin reactions and serum alanine aminotransferase ALT). Results Of 110 randomized participants, 102 participants completed the end-of-treatment assessment. After three cycles, TER was significantly higher in the intervention group than the control group (60.00% vs. 34.55%, p = 0.013). Adjusted post-treatment NRS pain intensity was lower in the intervention group (3.08 ± 0.22 vs. 4.55 ± 0.22; p 0.001). Menstrual pain duration showed a non-significant trend favoring the intervention (1.59 ± 0.07 vs. 1.76 ± 0.07 days; p = 0.087). The intervention group also demonstrated lower TCM syndrome scores (20.73 ± 1.85 vs. 27.98 ± 1.85; p = 0.007) and improved CMSS severity (12.82 ± 1.53 vs. 18.29 ± 1.53; p = 0.013) and duration scores (14.79 ± 1.51 vs. 20.41 ± 1.51; p = 0.010). Serum PGF2α decreased and PGE2 increased in the intervention group, with significant between-group differences for PGF2α ( p = 0.027), PGE2 ( p = 0.041), and PGF2α/PGE2 ratio ( p 0.001). Rescue ibuprofen use differed significantly between groups ( p = 0.033), favoring the intervention. No adverse events or ALT abnormalities were observed. Conclusion Dysmenorrhea Patch acupoint application for three menstrual cycles improved clinical response and reduced pain intensity and symptom burden in women with Qi stagnation and blood stasis type PD, with favorable prostaglandin changes and good safety. Larger and longer-term studies with rigorous assessment of blinding and concomitant medication effects are warranted. Clinical Trial Registration https://www.chictr.org.cn/showprojEN.html?proj=60256 , identifier ChiCTR2000037102.