A Preliminary Study on the Efficacy of Danggui Shaoyao San and Cuscuta Chinensis in Patients With Primary Dysmenorrhea

Study Overview This study investigates the efficacy of two traditional Chinese medicine (TCM) formulations, Danggui Shaoyao San (DSS) and Cuscuta Chinensis (Tu Si Zi), in managing primary dysmenorrhea (PD). PD is a prevalent condition characterized by painful menstrual cramps, often accompanied by physical and emotional symptoms such as fatigue, irritability, nausea, and breast tenderness. Existing treatment options, including NSAIDs and hormonal contraceptives, are effective for symptom relief but may cause side effects or fail to address associated non-pain symptoms, emphasizing the need for complementary or alternative therapies.

Study Design The trial is a randomized, double-blind, placebo-controlled study. Participants meeting the inclusion criteria will be randomly assigned to one of four groups: DSS, Tu Si Zi, a combination of DSS and Tu Si Zi, or placebo. Each treatment will be administered 3 to 7 days prior to menstruation and continued until 3 days post-menstruation. The intervention spans two consecutive menstrual cycles.

The primary outcomes will be changes in pain intensity measured by the Visual Analogue Scale (VAS) and improvements in menstrual symptoms evaluated using the Menstrual Symptom Questionnaire (MSQ). Secondary outcomes include an exploration of the correlation between TCM pulse diagnosis, TCM constitution types, and therapeutic responses, providing insights into the personalization of treatment based on TCM differentiation (辨證).

Rationale Danggui Shaoyao San, a classic TCM formula, is widely used for blood and qi regulation, reducing uterine contractions, and alleviating menstrual pain. Research suggests that it has anti-inflammatory properties and supports immune regulation, making it suitable for patients with blood stasis and qi stagnation patterns. Conversely, Cuscuta Chinensis, traditionally used to nourish kidney essence and yang, may be effective for individuals with kidney deficiency patterns associated with PD. The combination of these formulas could potentially enhance therapeutic outcomes by addressing multiple pathophysiological mechanisms simultaneously.

Methods Eligible participants are women aged 20-45 years with regular menstrual cycles (21-42 days) and a history of moderate to severe menstrual pain (VAS > 3) persisting for at least three cycles. Participants will be excluded if they have secondary dysmenorrhea caused by underlying conditions (e.g., endometriosis), use intrauterine devices, are pregnant or breastfeeding, or are taking anticoagulants or other conflicting medications.

Participants will undergo the following assessments:

Pain and Symptom Evaluation

VAS: Pain intensity will be measured before, during, and after treatment to assess changes.

MSQ: This tool evaluates menstrual symptoms such as mood changes, fatigue, nausea, diarrhea, and abdominal bloating, offering a comprehensive view of symptom burden.

TCM Diagnostic Tools

Pulse Diagnosis: Using a pulse diagnosis device, data from the radial artery will be collected to assess energy distribution across the pulse positions (cun, guan, chi).

TCM Constitution Questionnaire: Participants will complete a validated questionnaire to determine their constitution type, providing context for their treatment response.

Clinical and Demographic Data Collection

Baseline characteristics, including age, BMI, vital signs, and analgesic use, will be recorded.

Blinding and Randomization Randomization will be performed using a block randomization scheme. All participants, investigators, and outcome assessors will be blinded to group assignments. The study medications, prepared in identical capsules, will be indistinguishable from the placebo. The placebo group will serve as a control to isolate the specific effects of the TCM interventions.

Data Analysis The study will use repeated measures ANOVA to evaluate within-group and between-group differences in VAS and MSQ scores over time. Multivariate linear regression will identify variables influencing treatment outcomes, including constitution type and baseline symptom severity. Statistical significance will be set at p < 0.05.

Significance and Expected Outcomes This trial aims to determine whether DSS, Tu Si Zi, or their combination can effectively alleviate menstrual pain and associated symptoms, providing a holistic approach to managing PD. Additionally, it seeks to validate the scientific basis of TCM differentiation in treatment selection, enhancing its integration into modern clinical practice. The findings will inform clinicians and patients about effective, personalized therapeutic options and expand the evidence base for TCM in managing gynecological conditions.

Ethical Considerations The study has been approved by the Institutional Review Board (IRB) of Taichung Tzu Chi Hospital. Participants will provide written informed consent before enrollment. All data will be securely stored and anonymized to protect participant privacy.