BACKGROUND
Astronauts experience both orthostatic hypotension and space motion sickness during re-entry. Midodrine, an alpha1-adrenergic agonist, is used to treat orthostatic hypotension. Promethazine, a histamine H1-receptor antagonist, is prescribed for space motion sickness. Many astronauts need
A variety of physiological changes are experienced by astronauts during both short- and long-duration space missions. These include space motion sickness, spatial disorientation, orthostatic hypotension, muscle atrophy, bone demineralization, increased cancer risk, and a compromised immune system.