Effects of ramelteon on insomnia symptoms induced by rapid, eastward travel

Objective: Ramelteon, an MT1/MT2 melatonin receptor agonist, was evaluated for its ability to reduce sleep-onset difficulties associated with eastward jet travel. Methods: Healthy adults (n = 110) with a history of jet lag sleep disturbances were flown eastward across five time zones from Hawaii to the east coast of the US. Ramelteon 1, 4, or 8 mg or placebo was administered 5 min before bedtime (local time) for four nights. Sleep parameters were measured using polysomnography (PSG) on Nights 2, 3, and 4. Next-day residual effects were assessed using psychomotor and memory function tests. Results: Compared to placebo, there was a significant decrease in mean latency to persistent sleep (LPS) on Nights 2-4 with ramelteon 1 mg (-10.64 min, P = 0.030). No consistent significant differences were observed with ramelteon vs. placebo on measures of next-day residual effects except on Day 4 where participants in all ramelteon groups performed significantly worse on the immediate memory recall test compared with placebo (P <= 0.05). The incidence of adverse events was similar for ramelteon and placebo. Conclusion: After a 5-h phase advance due to eastward jet travel, ramelteon 1 mg taken before bedtime for four nights reduced mean LPS relative to placebo in healthy adults. (C) 2010 Elsevier B.V. All rights reserved.