Dose-Response Effects of Tiagabine on the Sleep of Older Adults

To evaluate the dose- response effects of tiagabine on sleep and safety measures in healthy older adults.Randomized, double-blind, Latin-square design.Sleep laboratory.Twenty-four healthy older adults (11 men, 13 women; mean age 68.0 +/- 6.2 years)Tiagabine 2, 4, or 8 mg, or placebo, each given on two consecutive nights.Polysomnography revealed that compared with placebo, tiagabine 4 mg increased total sleep time, reduced wake after sleep onset, and increased minutes of slow-wave sleep. Tiagabine 8 mg decreased wake after sleep onset, increased slow-wave sleep, and improved a sleep-continuity index. No differences were seen between the 2-mg dose and placebo. Subjective ratings indicated fewer awakenings with the 8-mg dose. Central nervous system adverse events were somewhat higher in the 8-mg condition only. Measures of morning performance were minimally affected.Research with tiagabine at dosages of 8 mg or less appears warranted in elderly clinical populations.