The astronaut opened his helmet to launch a glass ball into space. Mushrooms grow behind his helmet. On the top of which a woman holds a disco ball by a rope.
[Space] – Masha Bo
By the beginning of 2020, over 560 individuals have flown in space, with duration ranging from 15 min to 437 days. Among these were seven ‘space tourists’, some with known medical problems, who typically spent over a week onboard the International Space Station (ISS). As we enter a new era of commercialized spaceflights, more individuals will be able to travel to low Earth orbit or even to deep space.
Space travel imposes multiple challenges to the human body due to microgravity, radiation, confinement, isolation, changes in circadian rhythm, and stress. The effect depends on the duration of the mission and its destination and varies with the phase of the spaceflight. During the first days of flight, participants may develop space motion sickness. Fluids shift to the central compartment of the body and the head with subsequent changes in the concentration of albumin and other plasma components and in renal metabolism. Within a few days, fluid redistribution is compensated by diuresis and loss of plasma and extracellular fluid volume. Longer stays in space have many physiological consequences, including loss of bone mineralization and muscle strength, reduced cardiovascular capacity, alterations in immune function and in the microbiome, and neuro-ocular symptoms. Those changes can prompt medication consumption while potentially altering drug handling by the body, as was recently reviewed in more detail. The present editorial adds recent examples of the complexities of drug treatment in space, comparatively summarizes the available pharmacokinetic parameters in astronauts, and highlights fields of knowledge and lack thereof.