Improvement in self-reported, but not actigraphic, sleep measures with suvorexant in people with well-controlled Restless Legs Syndrome and persistent insomnia.

BACKGROUND

Sleep disturbance remains common in people with Restless Legs Syndrome (RLS), even after RLS symptoms are sufficiently controlled with medication. We conducted a placebo-controlled crossover trial to examine the efficacy of suvorexant in improving sleep quality and quantity in people with well-controlled RLS and persistent insomnia.

METHODS

In this double-blind, randomized, placebo-controlled crossover trial, 34 participants (70.6 % female, mean age = 62.7) with well-controlled RLS were randomized to placebo or suvorexant (10-20 mg) for 6 weeks, followed by a 2-week washout and then the opposite treatment. Study inclusion required an IRLS score <15, insomnia diagnosis per DSM-5, and a diary-reported combined Sleep Onset Latency (SOL) and Wake After Sleep Onset (WASO) > 45 min and a Total Sleep Time (TST) < 7 h on 7/14 baseline nights. The primary outcome was actigraphically-derived TST, and secondary outcomes were Insomnia Severity Index (ISI) score and actigraphically-derived WASO. Data for all sleep metrics were collected at baseline and for the last two weeks of each treatment period.

RESULTS

There were no significant improvements in actigraphically-derived TST (p = 0.58) or WASO (p = 0.99) while taking suvorexant compared to placebo. However, there were significant reductions in insomnia symptoms, measured by the ISI, as well as increases in diary-reported TST (p = 0.01) while taking suvorexant compared to placebo. The most commonly reported side effect of suvorexant was fatigue (29.4 %).

CONCLUSIONS

We observed no significant differences between treatments in actigraphically-derived sleep measures, but support for suvorexant's benefit for overall insomnia and self-reported quantity of sleep in people with well-controlled RLS who continue to suffer from insomnia.

CLINICAL TRIALS REGISTRATION NUMBER: NCT04706091.