Objective:

To explore safety & efficacy of suvorexant for insomnia in Parkinson disease and to assess viability of a larger study. 

Background:

Parkinson’s disease (PD) has a high prevalence of sleep disorders, including insomnia, yet few studies exist of treatments for insomnia in PD. Suvorexant, an FDA-approved medication for insomnia in the general population, has not previously been studied in this population.

Design/Methods:

This was a randomized, double-blind, placebo-controlled, crossover trial of suvorexant for insomnia in PD. It involved two 4-week treatment periods separated by a two-week washout period, with suvorexant 10 or 15 mg nightly or a placebo. The primary outcome was change in sleep efficiency, with secondary outcomes that included Wakefulness After Sleep Onset (WASO) and Latency to Persistent Sleep (LPS). Other secondary outcomes included Clinician’s Global Impression of Change (CGI-C); Montreal Cognitive Assessment (MoCA); Insomnia Severity Index (ISI); Epworth Sleepiness Scale (ESS); Beck Depression Inventory (BDI-II); Beck Anxiety Inventory (BAI); and Subject’s Global Impression of Change (SGI-C).

Results:

In this crossover trial with 21 subjects, suvorexant did not significantly improve sleep efficiency compared to placebo. However, there was a trend with suvorexant towards greater improvement in sleep maintenance (reduced WASO) and in sleep onset (reduced LPS). Additionally, there was significant improvement on the ISI with suvorexant relative to placebo, and a trend favoring suvorexant in CGI-C. Suvorexant was well-tolerated, with no serious or severe adverse events, although two subjects withdrew due to drowsiness. Suvorexant did not worsen cognition, depression, anxiety, or daytime sleepiness.

Conclusions:

This study is the first randomized trial of suvorexant in patients with Parkinson disease. While it did not meet its primary endpoint, several secondary outcome measures showed a trend favoring suvorexant over placebo. Larger trials in this population are warranted, but recruiting this population for a study requiring multiple overnight polysomnograms proved more difficult than expected.