title: Effects of prolonged-release melatonin and zolpidem on postural stability in older adults.
abstract: OBJECTIVE
  A prolonged-release formulation of melatonin (PR-M) is indicated for insomnia in patients aged 55 years and older. Because hypnotics result in impairments of body sway, it was important to evaluate the effect of 2 mg PR-M on postural stability in older adults at night.
  
  
  METHODS
  Twenty-four healthy volunteers (12 women, 12 men, aged 55-64 years) completed a randomized, double-blind, single-dose, three-way crossover study of postural stability of PR-M 2 mg, zolpidem 10 mg (active control) or placebo. Subjects were tested for body sway 30 min before, 1.5 and 4 h after dosing. Parameters tested were the area of the 95% confidence ellipse enclosing the center of pressure (COP; [A95]) and COP path length.
  
  
  RESULTS
  Zolpidem significantly increased the A95 (both eyes conditions at all time points) and path length of COP. PR-M had no effect on A95 (both "eyes closed" and "eyes open" conditions at all time points) compared with placebo and increased COP path length by 10% at 4 h post-dose in open but not closed eyes condition. No serious adverse events were observed.
  
  
  CONCLUSIONS
  In older adults, evening PR-M intake did not impair postural stability during the night. The postural instability with zolpidem demonstrated assay sensitivity and validated the outcome.
authors.affiliation: Forenap Pharma, Rouffach, France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Otmani
authors.forename: Deborah
authors.initials: D
authors.lastname: Metzger
authors.forename: Nathalie
authors.initials: N
authors.lastname: Guichard
authors.forename: Philippe
authors.initials: P
authors.lastname: Danjou
authors.forename: Tali
authors.initials: T
authors.lastname: Nir
authors.forename: Nava
authors.initials: N
authors.lastname: Zisapel
authors.forename: Amnon
authors.initials: A
authors.lastname: Katz
mesh_terms: D000704:Analysis of Variance; D000975:Antioxidants / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D008875:Middle Aged; D004856:Postural Balance / Q000187:drug effects*; D011725:Pyridines / Q000494:pharmacology*; D013997:Time Factors; D000077334:Zolpidem
chemical_list: D000975:Antioxidants; D006993:Hypnotics and Sedatives; D011725:Pyridines; D000077334:Zolpidem; D008550:Melatonin