Doctors advise against taking expired medications, but what do you do if you’re stationed on Mars with no pharmacy in sight? That’s the main question posed by Duke University School of Medicine researchers in a study published on July 23 in npj Microgravity. Researchers conclude that if astronauts ever intend to travel beyond the International Space Station, much more needs to be done to ensure their health.
Although many prescription drugs, particularly liquids like insulin and nitroglycerin, become more harmful after expiring, others like ibuprofen may simply reduce in efficacy. Either way, it generally takes years before many common medications expire. And since the longest stint in space is currently Mark Vande Hei’s 341-day ISS residency, such problems have not been an issue so far in space exploration. Even if dire emergencies occur, returning home takes a matter of hours, not months—provided there are no technical difficulties.
[Related: Why space lettuce could be the pharmacy astronauts need.]
Astronauts, however, can’t afford to navigate expiration dates in future high-risk, unprecedented missions that push the boundaries of human exploration. Experts still don’t fully understand just how harsh the environments of space, the moon, and Mars may affect the long term potency and stability of drugs. Multiple past studies indicate microgravity environments may affect drugs in at least some capacity.
“It doesn’t necessarily mean the medicines won’t work, but in the same way you shouldn’t take expired medications you have lying around at home, space exploration agencies will need to plan on expired medications being less effective,” Daniel Buckland, an associate professor of emergency medicine and senior study author, said in an accompanying statement on Tuesday.
After obtaining the International Space Station’s medication list using a Freedom of Information Act request, Buckland along with pharmacy resident and study co-author Thomas Diaz analyzed them using a database of international medication expiration dates. Of the 91 drugs examined, 54 have a shelf life of 36 months or less. Using even the most optimistic estimates, Buckland, Diaz, and their colleagues believe around 60 percent of a crew’s pharmacy supplies would expire before finishing a deep space mission. Assessing the scenario more conservatively, virtually all of them may either lose efficacy or become useless, if not dangerous.
At least 14 medications might not even last two years into a hypothetical mission. According to the study, these could include “one advanced life support medication… two corticosteroids, one local anesthetic, one topical urinary jelly, two antibiotics, one antipsychotic, one inhaler, and one ear wax removal medication.”
Given that so little is known about space travel’s effects on medications, the team’s review focused exclusively on the inability to resupply a mission to Mars, which experts believe will take 24-36 months.
“Ultimately, those responsible for the health of spaceflight crews will have to find ways to extend the expiration of medications to the complete mission duration or accept the elevated risk associated with administration of an expired medication,” the team writes in their paper.
The authors suggest potential solutions from NASA and other international agencies could involve designing self-sufficient pharmacy equipment, either in space or for deployment on Mars.