PT661. The effect of Yokukansan, a traditional herbal medicine, on sleep disturbances and anxiety symptoms in restless legs syndrome

Abstract

Abstract Objective: Dopaminergic agonists such as pramipexole are now considered the first-line treatment for restless legs syndrome (RLS). Dopaminergic agonist, however, sometimes fail to treat RLS. It is important to identify the factors that may prevent therapeutic agents from improving RLS symptoms. This study aims to examine whether anxiety symptoms affect the control of RLS symptoms in patients treated with pramipexole. We also investigated the effect of a herbal prescription, Yokukansan (YKS), on RLS and comorbid anxiety symptoms. Patients and Methods: Thirty-three patients with secondary RLS were enrolled in a prospective study. RLS symptoms and anxiety symptom were evaluated using the International RLS Study Group rating scale (IRLS) and Hamilton Anxiety Scale (HAM-A), respectively. Subjective sleep quality and daytime somnolence were also examined with Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS), respectively. After being treated with pramipexole for 4 weeks, the subjects were divided into 2 groups based upon the IRLS score. The responder group included subjects whose IRLS scores were less than 10 after 4-week treatment, and the poor-responder group included those whose IRLS scores were 10 or over. (1) HAM-A scores were compared between the responder group and the poor-responder group. (2) In the poor-responder group, YKS was prescribed in combination with pramipexole. We also examined the effect of pramipexole and YKS (4 weeks) on IRLS, HAM-A, PSQI, and ESS. The local IRB approved this study. All patients gave written consent according to institutional guidelines and the tenets of the Declaration of Helsinki. Results: There was no difference in basal IRLS scores between two groups. The mean HAM-A score after pramipexole treatment in the poor-responder group (n=9) was higher than that in the responder group (n=24). Treatment with pramipexole and YKS for 4 weeks improved RLS and anxiety symptoms. Conclusions: Anxiety symptoms may affect the treatment outcome in patients with RLS. YKS was demonstrated to be effective for RLS and comorbid anxiety symptoms.