A Kampo medicine, kamishoyosan, ameliorates menstruation-associated symptoms in patients with premenstrual syndrome: An exploratory open-label, randomized controlled trial

Premenstrual syndrome (PMS) is a psychological or physical symptom. We conducted an open-label, randomized, exploratory trial with the aim of evaluating the efficacy and safety of kamishoyosan (KSS) for PMS. KSS was administered orally during three menstrual cycles. The primary endpoint was the change in the premenstrual Menstrual Distress Questionnaire (MDQ) total score. The secondary endpoints included MDQ total and subscale scores, a daily symptom questionnaire, the Work Productivity and Activity Impairment (WPAI) Questionnaire, overall impressions, sleep status, and heart rate. A total of 50 patients were enrolled. The primary endpoint, the premenstrual MDQ total score, was significantly ameliorated after KSS treatment. Furthermore, KSS reduced MDQ scores during the menstrual cycle. Among the MDQ subscales, KSS decreased score of pain, concentration, behavioral change, and negative feelings during the premenstrual cycle. In addition, hyperthymia reduced during the menstrual cycle. The results of the daily symptom questionnaire indicated that KSS treatment alleviated irritability, easy anger, anxiety, emotional instability, abdominal distension, coldness, and stiff shoulders.The WPAI activity impairment score was lower in the KSS group, and overall impression favoured in KSS treatment.. The only adverse event related to KSS was headache in one case. These exploratory findings suggest that KSS may improve menstrual-related symptoms in PMS.