Effect of temazepam on oxygen saturation and sleep quality at high altitude: randomised placebo controlled crossover trial

Objective: To determine the effects of temazepam on the quality of sleep and on oxygen saturation during sleep in subjects at high altitude. Design: Randomised, blinded, crossover, placebo controlled trial. Setting: Base camp at Mount Everest (altitude 5300 m). Subjects: 11 members of British Mount Everest Medical Expedition recently arrived at base camp. Intervention: Participants were randomly allocated to receive either temazepam 10 mg or placebo on their first night at base camp and the other treatment on the second night. Main outcome measures: Quality of sleep (assessed subjectively), mean arterial oxygen saturation value, and changes in saturation values (as measure of periodic breathing) while participants taking temazepam or placebo. Results: All participants noted subjective improvements in sleep. Mean saturation value remained unchanged when temazepam was compared with placebo (74.65% v 75.70%, P=0.5437). There were fewer changes in oxygen saturation when participants took temazepam and when measured as decreases >4% below the mean value of saturation each hour (P=0.0036, paired Student’s t test (two tailed)). Conclusions: Participants taking temazepam at 5300 m showed no significant drop in mean oxygen saturation values during sleep. Both the number and severity of changes in saturation during sleep decreased and the quality of sleep improved. This may be a result of a reduction in the number of awakenings and might lead to greater respiratory stability and fewer episodes of periodic breathing. This has the effect of improving the quality of sleep and reducing the number of periods of desaturation during sleep

Key messages

• Poor sleep at high altitude is common and may be due to a combination of physiological and physical factors
• Frequent arousals, periodic breathing, and episodes of oxygen desaturation lead to poor sleep and daytime symptoms of drowsiness and reduced performance
• In this study 10 mg temazepam improved subjective reports of the quality of sleep and reduced episodes of arterial desaturation, with no significant effect on mean oxygen saturation during sleep