Sleep changes after 4 consecutive days of venlafaxine administration in normal volunteers

Background: The purpose was to examine the effect of the antidepressant drug venlafaxine on sleep architecture and periodic leg movements of sleep (PLMS) in normal volunteers. Method: Eight normal volunteers were studied under laboratory sleep conditions as follows: 1 acclimatization night, 1 baseline night, and 4 consecutive nights of venlafaxine p.o. administration (75 mg during the first 2 nights and 150 mg the last 2 nights). Results: Venlafaxine increased both wake time and sleep stage I. Sleep stages II and III were reduced. REM sleep time was reduced after the first venlafaxine dose, and, by the fourth night, REM sleep was completely suppressed in all volunteers. Six of the eight volunteers showed PLMS at a frequency above 25 per hour. Conclusion: Venlafaxine produces several sleep disturbances, which include abnormal leg movements.