TEST OF MIDODRINE AS A COUNTERMEASURE AGAINST POSTFLIGHT ORTHOSTATIC
HYPOTENSION – LONG- AND SHORT-DURATION BIOLOGICAL INVESTIGATION (MIDODRINE-LONG
AND SDBI), TWO INVESTIGATIONS
Research Area: Cardiovascular and Respiratory Systems
Expeditions: 14- 17
Principal Investigator(s): ● Steven Platts, PhD, Johnson Space Center, Houston, Texas
RESEARCH OBJECTIVES
This investigation tests the ability of the drug Midodrine to reduce the incidence or severity of
orthostatic hypotension. If successful, it will be employed as a countermeasure to the dizziness
caused by the blood pressure decrease that many astronauts experience upon returning to the
Earth’s gravity.
EARTH BENEFITS
In addition to benefits for astronauts, millions of people on Earth suffer from orthostatic
hypotension and may benefit from information gained from this experiment.
SPACE BENEFITS
Orthostatic hypotension (low blood pressure while standing) is a significant problem to
astronauts returning from even short-term spaceflight, and the symptoms are more prevalent
with longer-term flights. Often when returning home, an astronaut's body is unable to maintain
blood pressure above the heart, which leads to decreased blood flow in the brain, resulting in
lightheadedness and even fainting. Currently used countermeasures to the problem, such as
increasing blood volume with saline, have not proven completely effective. If effective,
postflight Midodrine administration may provide a relatively simple method for preventing a
significant obstacle to long-term spaceflight, especially exploratory trips to the moon and Mars.
RESULTS
Midodrine is an FDA approved
drug used for treating orthostatic
hypotension (OH), which is a
sudden drop in blood pressure
(BP) upon standing or stretching
causing dizziness or fainting. This
study administered 10 mg of
Midodrine to a female space
shuttle crew member after
landing in a second flight who
had experienced head rush or
dizzy spell after a previous flight
to see if the drug is effective in
alleviating these symptoms. Her
heart rate, blood pressure, andJSC2005E15226 – View of European Space Agency (ESA) astronaut
Roberto Vittori and cosmonaut Sergei K. Krikalev participate in tilt
table tests on April 11, 2005, in Baikonur, Kazakhstan.