Sleep and pain in humans with fibromyalgia and comorbid insomnia: Double-blind, crossover study of suvorexant 20 mg versus placebo

Abstract

Study Objectives: The chronic pain disorder, fibromyalgia, is associated with sleep disturbance, typically sleep maintenance. No studies have evaluated the effect of sleep medication on pain sensitivity in this population. Suvorexant, an orexin antagonist approved for treatment of insomnia, was evaluated for effects on both sleep and the pain of fibromyalgia. Methods: Women age 21 to 65 years with fibromyalgia and comorbid insomnia (n = 10) were treated, double-blind, for 9 nights each with suvorexant, 20 mg and placebo in counterbalanced order. All were in good psychiatric and stable physical health and met American College of Rheumatology 2010 criteria for fibromyalgia and Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition criteria for insomnia. Screening 8-hour polysomnography (PSG) was used to rule out other sleep disorders. On nights 8 and 9 of each treatment 8-hour PSG were collected and on days 1 and 8 pain sensitivity was assessed at 1100 and 1500 hours by measuring finger withdrawal latency (FWL) to a radiant heat stimulus at 5 randomly presented intensity levels. Results: Suvorexant versus placebo increased total sleep time (7.2 versus 6.7 hours, P < .03) following suvorexant the previous night. Conclusions: Suvorexant 20 mg in patients with fibromyalgia, improved sleep time and reduced next-day pain sensitivity on assessments of FWL to a radiant heat stimulus.