Work

Hemodynamic effects of midodrine after spaceflight in astronauts without orthostatic hypotension.

Year: 2006

Type: article

Abstract: INTRODUCTION: Orthostatic hypotension and presyncope are common and potentially serious risks for astronauts returning from space. Susceptible subjects fail to generate an adequate adrenergic response to upright posture. The alpha-1 adrenergic agonist, midodrine, may be an effective countermeasure. We tested the hypothesis that midodrine would have no negative hemodynamic effect on healthy astronauts returning from space. METHODS: Five male astronauts participated in preflight and post-flight tilt testing on a control flight as well as on the test flights, where midodrine (10 mg, orally) was administered after landing approximately 1 h before testing. RESULTS: None of these astronauts exhibited orthostatic hypotension or presyncope before or after either flight. Midodrine did not cause any untoward reactions in these subjects before or after flight; in fact, a modest beneficial effect was seen on postflight tachycardia (p = 0.036). DISCUSSION: These data show that midodrine protected against post-spaceflight increases in heart rate without having any adverse hemodynamic effects on non-presyncopal, male astronauts. Among these subjects, midodrine was a safe cardiovascular countermeasure.

Source: PubMed

Authors: Steven H Platts, Michael G Ziegler, Wendy W Waters, Janice V Meck

Institution: Universities Space Research Association

Language: English

Topic: Spaceflight effects on biology

Subfield: Physiology (medical)

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: green

Funders: National Aeronautics and Space Administration, National Institutes of Health, Johnson Space Center, National Center for Research Resources

Awards: G70132605, General Clinical Research Center