The Effects of Milnacipran on Sleep Disturbance in Fibromyalgia: A Randomized, Double-Blind, Placebo-Controlled, Two-Way Crossover Study

Objective: This study examined the effects of milnacipran on polysomnographic (PSG) measures of sleep and subjective complaints in patients with fibromyalgia and disturbed sleep. Methods: This was a single-site, double-blind, placebo-controlled, two-period crossover PSG study. Eligible subjects (aged 28-72 y) were randomized (1:1) to milnacipran (100 mg/d) or placebo for crossover period 1, and vice versa for period 2. Each crossover period comprised a dose-escalation and dose-maintenance phase, with a 2-w taper/washout between periods. In-laboratory PSGs were collected at baseline, and at the end of each treatment period. The primary endpoints were the difference in PSG-recorded wake after sleep onset (WASO), number of awakenings after sleep onset (NAASO), and sleep efficiency (SE) between 4 w of maintenance treatment with milnacipran and placebo. Other PSG measures, subject-rated sleep, fatigue, physical functioning, and pain were assessed. Post hoc analysis was performed in subjects showing at least 25% reduction in pain from baseline in the Brief Pain Inventory Score (responders). Results: Of 19 subjects randomized, 15 completed both periods. Subjects treated with milnacipran showed no significant improvements in WASO and NAASO, but showed reduced SE (p = 0.049). Milnacipran did not show significant improvement in other PSG parameters or subjective endpoints. Two thirds of completers met responder criteria and additionally showed a significant improvement in daily effect of pain (p = 0.043) and subjective sleep quality (p = 0.040). Conclusion: The data suggest that milnacipran is not sedating in most patients with fibromyalgia and improvements in sleep are likely a result of pain improvement.