An open-labeled trial of ramelteon in idiopathic rapid eye movement sleep behavior disorder

Study Objectives: Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by REM sleep without atonia and elaborate motor activity in association with dream mentation. The melatonin receptor agonist ramelteon has been documented as being effective in two patients with secondary RBD. However, there are no reports on ramelteon treatment for idiopathic RBD. Methods: In an open-labeled trial, we treated 12 consecutive patients with idiopathic RBD for at least 4 w with 8 mg ramelteon given within 30 min before bedtime. Results: Ramelteon treatment did not have a clear effect on REM sleep without atonia or an RBD severity scale measured by video-supported polysomnography. However, clinical assessment using a visual analog scale showed a trend toward significance and there were also definitely positive changes in some individual cases. Ramelteon was well tolerated in most patients, with minor side effects. Conclusions: Considering that ramelteon is associated with few side effects, further study may ascertain whether patients with RBD could be effectively treated by ramelteon, especially when clonazepam may not be suitable due to its side effects. Commentary: A commentary on this article appears in this issue on page 643.