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Midodrine prevents orthostatic intolerance associated with simulated spaceflightMany astronauts after being weightless in space become hypotensive and presyncopal when they assume an upright position. This phenomenon, known as orthostatic intolerance, may interfere with astronaut function during reentry and after spaceflight and may limit the ability of an astronaut to exit a landed spacecraft unaided during an emergency. Orthostatic intolerance is more pronounced after long-term spaceflight and is a major concern with respect to the extended flights expected aboard the International Space Station and for interplanetary exploration class missions, such as a human mission to Mars. Fully effective countermeasures to this problem have not yet been developed. To test the hypothesis that alpha-adrenergic stimulation might provide an effective countermeasure, we conducted a 16-day head-down-tilt bed-rest study (an analog of weightlessness) using normal human volunteers and administered the alpha(1)-agonist drug midodrine at the end of the bed-rest period. Midodrine was found to significantly ameliorate excessive decreases in blood pressure and presyncope during a provocative tilt test. We conclude that midodrine may be an effective countermeasure for the prevention of orthostatic intolerance following spaceflight.
Document ID
Document Type
Reprint (Version printed in journal)
Ramsdell, C. D.
(Massachusetts General Hospital Boston, Massachusetts 02114, United States)
Mullen, T. J.
Sundby, G. H.
Rostoft, S.
Sheynberg, N.
Aljuri, N.
Maa, M.
Mukkamala, R.
Sherman, D.
Toska, K.
Yelle, J.
Bloomfield, D.
Williams, G. H.
Cohen, R. J.
Date Acquired
August 21, 2013
Publication Date
June 1, 2001
Publication Information
Publication: Journal of applied physiology (Bethesda, Md. : 1985)
Volume: 90
Issue: 6
ISSN: 8750-7587
Subject Category
Aerospace Medicine
Funding Number(s)
Distribution Limits
Non-NASA Center
NASA Discipline Cardiopulmonary
Clinical Trial

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