title: Dose-related effect of triazolam on postural sway.
abstract: Measurement of clinically relevant benzodiazepine drug effects at hypnotic and anxiolytic doses has been difficult because most measures are subjective, difficult to interpret, or relate to anesthetic doses. A potentially useful measure of drug effect is postural sway, which is a manifestation of the corrective mechanisms associated with the maintenance of upright posture. Postural sway was measured over 8 hours, with a biomechanics force platform, in six healthy male volunteers who received triazolam, 0.125, 0.250, or 0.375 mg, or placebo in a randomized double-blind study. Our results show a dose-dependent increase in postural sway measured as the elliptical area or the 95% confidence ellipse for the area covered by the subjects' sway. After triazolam, 0.250 and 0.375 mg, the area under the sway-time curve and peak effect increased significantly compared with placebo (p less than 0.05). The number of losses of balance when subjects stood on one foot also showed a significant increase with increased dose (p less than 0.05). The rate of loss of balance was positively correlated with the extent of postural sway (r = 0.802; p less than 0.001). The extent of sway when the subjects were drug free predicted this increase in a subject's postural sway with triazolam. Thus at hypnotic or anxiolytic doses of triazolam, computer-assisted force platform measures of sway provide a clinically relevant measure of drug effect. Measurement of drug-induced postural sway may be useful in persons at risk for falls, such as the elderly.
authors.affiliation: Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232.
authors.forename: D W
authors.initials: DW
authors.lastname: Robin
authors.forename: S S
authors.initials: SS
authors.lastname: Hasan
authors.forename: M J
authors.initials: MJ
authors.lastname: Lichtenstein
authors.forename: R G
authors.initials: RG
authors.lastname: Shiavi
authors.forename: A J
authors.initials: AJ
authors.lastname: Wood
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006207:Half-Life; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000187:drug effects*; D011187:Posture; D014229:Triazolam / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D014229:Triazolam