An efficacy, safety, and dose-response study of Ramelteon in patients with chronic primary insomnia

Sleep Med. 2006 Jan;7(1):17-24. doi: 10.1016/j.sleep.2005.09.004. Epub 2005 Nov 23.


Background and purpose: To evaluate the efficacy, safety, and dose response of Ramelteon, a novel highly selective MT1/MT2 receptor agonist, in patients with chronic primary insomnia.

Patients and methods: A randomized, multicenter, double-blind, placebo-controlled, five-period crossover study design was performed. A total of 107 patients, aged 18-64 years, were randomized into a dosing sequence that included 4, 8, 16, and 32 mg of Ramelteon and placebo. Patients received all five treatments, with a 5- to 12-day washout period between treatments, and served as their own controls. Medication was administered 30 min before habitual bedtime and polysomnographic monitoring. Next-day residual effects were assessed with two visual analog scales (mood and feeling), digit symbol substitution test (DSST), word-list memory tests (immediate recall and delayed recall), and a post-sleep questionnaire that ascertained patients' alertness and ability to concentrate.

Results: All tested doses of Ramelteon resulted in statistically significant reductions in latency to persistent sleep (LPS) and increases in total sleep time (TST). No next-day residual effects were apparent at any dose, as compared with placebo. There were no differences in the number or type of adverse events between any active treatment and placebo group. The most commonly reported adverse events were headache, somnolence, and sore throat.

Conclusions: Ramelteon demonstrated a statistically significant reduction in LPS and a statistically significant increase in TST, with no apparent next-day residual effects, in patients with chronic primary insomnia.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Chronic Disease
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Humans
  • Indenes / administration & dosage
  • Indenes / adverse effects*
  • Indenes / therapeutic use*
  • Male
  • Melatonin / metabolism*
  • Middle Aged
  • Polysomnography / methods
  • Sleep Initiation and Maintenance Disorders / diagnosis
  • Sleep Initiation and Maintenance Disorders / drug therapy*
  • Surveys and Questionnaires
  • Treatment Outcome


  • Indenes
  • ramelteon
  • Melatonin