title: Temazepam at high altitude reduces periodic breathing without impairing next-day performance: a randomized cross-over double-blind study.
abstract: The aim of the study was to examine the efficacy and safety of temazepam on nocturnal oxygenation and next-day performance at altitude. A double-blind, randomized, cross-over trial was performed in Thirty-three healthy volunteers. Volunteers took 10 mg of temazepam and placebo in random order on two successive nights soon after arrival at 5000 m, following a 17-day trek from 410 m. Overnight SaO(2) and body movements, and next-day reaction time, maintenance of wakefulness and cognition were assessed. Compared with placebo, temazepam resulted in a reduction in periodic breathing from a median (range) of 16 (0-81.3)% of the night to 9.4 (0-79.6)% (P = 0.016, Wilcoxon's signed-rank test), associated with a small but significant decrease in mean nocturnal SaO(2) from 78 (65-84)% to 76 (64-83)% (P = 0.013). There was no change in sleep latency (P = 0.40) or restlessness (P = 0.30). Temazepam had no adverse effect on next-day reaction time [241 (201-380) ms postplacebo and 242 (204-386) ms post-temazepam], maintenance of wakefulness (seven trekkers failed to maintain 40 min of wakefulness postplacebo, and four post-temazepam), cognition or acute mountain sickness. At high altitude temazepam reduces periodic breathing during sleep without an adverse effect on next-day reaction time, maintenance of wakefulness or cognition. The 2% reduction in mean SaO(2) post-temazepam is likely to be predominantly because of acclimatization, as by chance more trekkers took temazepam on the first night (19 versus 14). We conclude that at high altitude temazepam is effective in reducing periodic breathing, and is safe to use, without any adverse effect upon next-day performance.
authors.affiliation: Oxford Centre for Respiratory Medicine, Churchill Hospital, Headington, Oxford, UK. annabel@medex.org.uk
authors.forename: Annabel H
authors.initials: AH
authors.lastname: Nickol
authors.forename: Juliette
authors.initials: J
authors.lastname: Leverment
authors.forename: Paul
authors.initials: P
authors.lastname: Richards
authors.forename: Philippa
authors.initials: P
authors.lastname: Seal
authors.forename: Greg A
authors.initials: GA
authors.lastname: Harris
authors.forename: Jenifer
authors.initials: J
authors.lastname: Cleland
authors.forename: Gerald
authors.initials: G
authors.lastname: Dubowitz
authors.forename: David J
authors.initials: DJ
authors.lastname: Collier
authors.forename: James
authors.initials: J
authors.lastname: Milledge
authors.forename: John R
authors.initials: JR
authors.lastname: Stradling
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Morrell
mesh_terms: D000532:Altitude Sickness / Q000188:drug therapy*; D001288:Attention / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D009051:Mountaineering; D009390:Nepal; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D017286:Polysomnography / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects*; D020182:Sleep Apnea, Central / Q000188:drug therapy*; D013693:Temazepam / Q000627:therapeutic use*; D016896:Treatment Outcome; D014851:Wakefulness / Q000187:drug effects
chemical_list: D006993:Hypnotics and Sedatives; D013693:Temazepam; D010100:Oxygen