Temazepam at high altitude reduces periodic breathing without impairing next-day performance: A randomized cross-over double-blind study

University of Aberdeen, Aberdeen, Scotland, United Kingdom
Journal of Sleep Research (Impact Factor: 3.35). 01/2007; 15(4):445-54. DOI: 10.1111/j.1365-2869.2006.00558.x
Source: PubMed


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.

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Available from: Jim Milledge, Sep 08, 2014
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    • "While the current study is the first that validates actigraphy by comparison to polysomnography at altitude, the technique has been employed previously to evaluate the effects of hypoxia, acute mountain sickness, and drugs for treatment of altitude insomnia (Barash et al., 2001; Erba et al., 2004; Nickol et al., 2006) illustrating the role of actigraphy for investigation of sleep and its disturbances at altitude. One study revealed that temazepam induced a reduction in periodic breathing over the course of a trek to 5000 m (Nickol et al., 2006) but there was no change in actigraphic sleep latency or nocturnal restlessness. Another study assessing the effects of zolpidem and zaleplon on sleep at 3613 m (Beaumont et al., 2007) revealed a significant decrease in the number of wrist movements by both drugs compared to placebo. "
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    ABSTRACT: Data on sleep at altitude are scant due to the limited availability of polysomnography. Therefore, we investigated whether actigraphy might serve as a simple tool for monitoring sleep during altitude field studies. Fourteen mountaineers participating in studies on dexamethasone prophylaxis of high altitude pulmonary edema were monitored by actigraphy and polysomnography during 1 night at Zurich (490 m) and 4 nights at the Regina Margherita hut (4559 m). Total sleep time (TST) estimated by actigraphy was compared to polysomnography and subjective sleep quality. In 64 comparisons, mean differences±2SD (bias±limits of agreement) between actigraphy and polysomnography were 5±35 min for TST and 1±7% for sleep efficiency. Correlations between subjective and polysomnographic estimates of sleep efficiency and sleep latency were nonsignificant. Medians of nocturnal oxygen saturation were 96% at 490 m and 74%-81% during nights 1 to 4 at 4459 m (p<0.05 vs. 490 m). Medians of polysomnographic TST were similar at 490 m (451 min) and 4559 m (377-456 min during nights 1 to 4, p=NS) but the proportions of slow wave and REM sleep were reduced and arousals were more common (p<0.05 all instances). Actigraphy accurately estimates sleep efficiency and duration. Due to its portability and simple use and the potential application over several weeks, it is a convenient tool for investigating altitude effects on sleep during field studies.
    Preview · Article · Oct 2011 · High altitude medicine & biology
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    • "If still abnormal, prophylactic drug therapy is recommended: acetazolamide (250 mg b.i.d.), dexamethasone (2 mg b.i.d.), sildenafil (20 mg b.i.d.) [11,23], nifedipine slow release (20 mg b.i.d.). In the case of ventilatory (respiratory pump, periodic breathing) insufficiency with and without lung and heart failure: polysomnography should be performed in all patients, if necesssary with and without supplemental O2-breathing and/or mechanical aids at night (CPAP, BiPAP, IPPV, added dead space) and drug therapy [9,12,20,22]. "
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    • "Similarly,wedidnotfindadifferenceineitherthemeanor minimumsleepingSaO2betweensubjectswithandwithout PB.AstudybyNickoletal.(2006)studiedtheeffectsof temazepamonPB,overnightSaO2andnext-daycognitive performance;theyfoundthattemazepamdidreducePBbut wasassociatedwithasmallbutsignificantdecreasein overnightSaO2;thisdecreaseinSaO2may,however,bedue tothefactthatmostsubjectstooktemazepamonthefirstnight athighaltitude. "
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