As space agencies target Mars, one critical challenge is the limited shelf-life of medications. A recent study by Duke University School of Medicine reveals that more than half of the medications currently stocked for space missions would expire before a Mars mission concludes. This emphasizes the crucial demand for strategies to safeguard astronauts’ health during prolonged space journeys.

The study highlights a major hurdle for space exploration. Drugs like pain relievers, antibiotics, allergy medications, and sleep aids might lose their effectiveness over the three-year duration of a Mars mission. Expired medications can lose their strength significantly, posing a risk to astronauts’ health and mission success.

“Space exploration agencies will need to plan on expired medications being less effective,” said Dan Buckland, senior study author and an assistant professor of emergency medicine at Duke University School of Medicine and an aerospace medicine researcher. “This could mean astronauts end up relying on ineffective or even harmful drugs.”

In contrast to Earth, where medical supplies can be quickly replenished, astronauts on a Mars mission must rely solely on the medications they carry due to their isolation. The study examined the International Space Station’s (ISS) formulary and found that 54 of the 91 medications analyzed had a shelf-life of 36 months or less. Optimistically, approximately 60% of these medications would expire before a Mars mission concludes. Under more conservative assumptions, the figure jumps to 98%. Even with Earth-like stability conditions, most medications will expire before the Mars mission ends.

Addressing this challenge requires space agencies to explore methods to prolong medication expiration, opt for drugs with extended shelf lives, or enhance the number of medications brought on board.

“I don’t see a technical limitation to making medications that last long enough, and the current medications may already last longer than the current dates provided by regulatory agencies,” Buckland told ZME Science. “However, what the study concluded is that the manufacturer or some other appropriate organization would have to do the research and certification necessary to prove that the medication retains its efficacy past 36 months, or that the space agency or individual crew member needs to accept the risk of possibly needing to take expired medications.” 

The study did not consider accelerated degradation due to space’s harsh environment, including radiation, which could further reduce the effectiveness of medications.

“There has been a fair amount of research into the effects of radiation exposure and other spaceflight hazards, and there are effects, but the ability to resupply frequently on the ISS has prevented any of these issues from becoming clinically relevant so far,” said Buckland, also deputy chair of the Human System Risk Board at NASA.

“Those responsible for the health of space flight crews will have to find ways to extend the expiration of medications to complete a Mars mission duration of three years, select medications with longer shelf-lives, or accept the elevated risk associated with administering expired medication,” said co-author Thomas E. Diaz, a pharmacy resident at The Johns Hopkins Hospital in a press release.

In the press release, Buckland emphasized the critical role of a consistently restocked pharmacy in preventing minor health issues from escalating and impacting the mission.

“Prior experience and research show astronauts do get ill on the ISS, but there is real-time communication with the ground and a well-stocked pharmacy that is regularly resupplied, which prevents small injuries or minor illnesses from turning into issues that affect the mission,” he said. “Astronauts are human. Healthy and well-trained humans, but still humans doing a tough job in an extreme environment.”

The findings appeared in the journal npj Microgravity.