Clonazepam for probable REM sleep behavior disorder in Parkinson's disease: A randomized placebo-controlled trial

Background Clonazepam is considered to be a first-line treatment for rapid eye movement sleep-related behavior disorder (RBD) in Parkinson's disease (PD). The purpose of this study was to determine the short-term efficacy and safety of clonazepam for the treatment of probable RBD (pRBD) in patients with PD. Methods: We conducted a four-week, randomized, double-blind, placebo-controlled trial of clonazepam (0.5 mg/day at bedtime) compared to a placebo for RBD symptoms in patients with PD. Patients aged 30 years or older who had a caregiver that could observe RBD symptoms were recruited between April 2015 and February 2016. The primary outcome was the Clinical Global Impressions-Improvement (CGI-I) score at week four, and we compared scores between the clonazepam and placebo groups. Results: A total of 40 patients were enrolled, with 20 assigned to receive clonazepam and 20 to receive the placebo. The CGI-I score at four weeks indicated an improvement in RBD symptoms in both the clonazepam (median score [minimum, maximum] = 2 [1,5]) and placebo (3 [1,6]) groups, with no significant difference between the groups (p = .253). The secondary outcomes were not significantly different between the clonazepam and placebo groups. Conclusions: Both clonazepam and placebo tended toward improvement on pRBD symptoms in patients with PD. No firm conclusion on efficacy of clonazepam was drawn due to limitations in the study design. This study emphasized the importance of conducting future large-scale, randomized trials with better assessment tools and polysomnography to provide evidence for the benefit of clonazepam.