Scientists have shown that medicines lose their potency more rapidly in outer space.
The peculiar conditions away from the earth - including weaker gravity and higher radiation - could be to blame, according to the research by NASA’s Johnson Space Center.
On earth, medication is typically designed to be stored for a couple years from the manufacture date.
The International Space Station: Boxes of medication were flown to the International Space Station and tested for effectiveness
But they always need to be kept in precise conditions to retain their effectiveness, such as away from direct sunlight or in a cool, dry space.
The authors of the study said longer space missions have increased the need for astronauts to take medicines.
So they investigated whether the unique environment of space - including radiation, vibrations, microgravity, a carbon dioxide rich environment and variations in humidity and temperature - affected drugs’ effectiveness.
Four boxes of drugs, containing 35 different medications, were flown to the International Space Station.
Meanwhile, four identical boxes were kept in controlled conditions at the Johnson Space Center.
The boxes came back to earth after varying lengths of time in space.
One was there for just 13 days, whereas another spent 28 months on the space station.
The study concluded: ‘A number of formulations tested had a lower potency after storage in space with consistently higher numbers of formulations failing United States Pharmacopeia potency requirement after each storage period interval in space than on Earth.
‘This reduction in potency of flight samples occurred sooner than the labelled expiration date for many formulations suggesting that storage conditions unique to the spacecraft environment may influence stability of pharmaceuticals in space.’