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Temazepam, but not zolpidem, causes orthostatic hypotension in astronauts after spaceflightInsomnia is a common symptom, not only in the adult population but also in many astronauts. Hypnotics, such as temazepam (a benzodiazepine) and zolpidem (an imidazopyridine), are often taken to relieve insomnia. Temazepam has been shown clinically to have hemodynamic side effects, particularly in the elderly; however, the mechanism is not clear. Zolpidem does not cause hemodynamic side effects. The purpose of this study was to determine whether the use of different hypnotics during spaceflight might contribute significantly to the high incidence of postflight orthostatic hypotension, and to compare the findings in astronauts with clinical research. Astronauts were separated into three groups: control (n = 40), temazepam (15 or 30 mg; n = 9), and zolpidem (5 or 10 mg; n = 8). In this study, temazepam and zolpidem were only taken the night before landing. The systolic and diastolic blood pressures and heart rates of the astronauts were measured during stand tests before spaceflight and on landing day. On landing day, systolic pressure decreased significantly and heart rate increased significantly in the temazepam group, but not in the control group or in the zolpidem group. Temazepam may aggravate orthostatic hypotension after spaceflight when astronauts are hemodynamically compromised. Temazepam should not be the initial choice as a sleeping aid for astronauts. These results in astronauts may help to explain the hemodynamic side effects in the elderly who are also compromised. Zolpidem may be a better choice as a sleeping aid in these populations.
Document ID
Document Type
Reprint (Version printed in journal)
Shi, Shang-Jin (Wyle Laboratories Houston, Texas, United States)
Garcia, Kathleen M.
Meck, Janice V.
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Journal of cardiovascular pharmacology
Volume: 41
Issue: 1
ISSN: 0160-2446
Subject Category
Aerospace Medicine
Distribution Limits
STS Shuttle Project
Flight Experiment
short duration
NASA Discipline Cardiopulmonary