Latency to persistent sleep

In controlled clinical trials in patients with primary insomnia, ramelteon 4-32 mg demonstrated significant reduction in latency to persistent sleep (LPS) compared with placebo. In elderly patients, objective and subjective LPS were also reduced at doses of 4 and 8 mg. Data on total sleep time are more variable,... 

Mini L, Wang-Weigand S, Zhang J. Ramelteon 8 mg/d versus placebo in patients with chronic insomnia post hoc analysis of a 5-week trial using 50% or greater reduction in latency to persistent sleep as a measure of treatment effect. Clin Ther 2008 30(7) 1316-23. 

SWA slow wave activity (assessed by power spectral analysis) EPS latency to onset of persistent sleep WASO wake after sleep onset SE sleep efficiency (total sleep time/time in bed x 100) TST total sleep time sleep stages (stage 1, 2, 3,4) SWS slow wave sleep (stage 3 + 4) REM rapid eye movement sleep NREM non-rapid eye movement sleep NSS number of stage... 

Three doses of zaleplon have been compared with placebo in outpatients with insomnia in a 4-week study (11). During week 1, sleep latency was significantly shorter with zaleplon 5, 10, and 20 mg than with placebo. The significant reduction in sleep latency persisted to week 3 with zaleplon 10 mg and to week 4 with zaleplon 20 mg. Compared with placebo, zaleplon 10 mg and 20 mg also had significant positive effects on sleep duration, number of awakenings, and sleep quality. Pharmacological tolerance did not develop with zaleplon and there were no indications of rebound insomnia or withdrawal symptoms after discontinuation. There was no significant difference in the frequency of adverse events with zaleplon compared with placebo. The authors concluded that zaleplon provides effective treatment of insomnia with a favorable safety profile. 

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