A Randomized, Double-blind, Placebo-controlled, Multicenter, 28-day, Polysomnographic Study of Gabapentin in Transient Insomnia Induced by Sleep Phase Advance

Study Objective: To evaluate multiple doses of gabapentin 250 mg on polysomnography (PSG) and participant-reported sleep assessments in a 5-h phase advance insomnia model.

Methods: Adults reporting occasional disturbed sleep received gabapentin 250 mg (n = 128) or placebo (n = 128). On Days 1 and 28, participants received medication 30 min before bedtime and were in bed from 17:00 to 01:00, ∼5 h before their habitual bedtime. Sleep was assessed by PSG, a post sleep questionnaire, and the Karolinska Sleep Diary. Next-day residual effects and tolerability were evaluated. On Days 2-27, participants took medication at home 30 min before their habitual bedtime.

Results: Treatment-group demographics were comparable. Gabapentin resulted in significantly less PSG wake after sleep onset (WASO) compared with placebo on Day 1 (primary endpoint, mean: 107.0 versus 149.1 min, p ≤ 0.001) and Day 28 (113.6 versus 152.3 min, p = 0.002), and significantly greater total sleep time (TST; Day 1: 347.6 versus 283.9 min; Day 28: 335.3 versus 289.1 min) (p ≤ 0.001). Participant-reported WASO and TST also showed significant treatment effects on both days. Gabapentin was associated with less %stage1 on Day 1, and greater %REM on Day 28, versus placebo. During home use, gabapentin resulted in significantly less participant-reported WASO and higher ratings of sleep quality. Gabapentin was well tolerated (most common adverse events: headache, somnolence) with no evidence of next-day impairment.

Conclusion: Gabapentin 250 mg resulted in greater PSG and participant-reported sleep duration following a 5-h phase advance on Day 1 and Day 28 of use without evidence of next-day impairment, and greater sleep duration during at-home use.