NASA is embarking on its most complex crewed missions to Mars and has detected another challenge in its way: drugs that expire. It is one of the lesser-known issues among other dangers of space radiation and a hostile environment, but many medicines astronauts may take with them could expire before their return to Earth.
A study led by Duke University School of Medicine found that more than half of the medications used in space were pain relievers, antibiotics, allergy medicines, and sleep aids already stockpiled on the shelves with an expiration date of three years or less. That is a serious concern when considering a mission to Mars could take approximately 36 months.
According to Dr. Dan Buckland, the senior study author and emergency medicine physician at Duke expired medication on Earth is generally less potent, but this degree of reduction in potency can’t be predicted. “The risk is that an illness later in a Mars mission would end up with a greater severity than had it occurred earlier in the mission before the medication has expired,” he said.
Buckland and colleagues used a Freedom of Information Act request to obtain the list of medications on board the International Space Station. While those medications on a Mars mission may not be specifically known, those on the ISS likely will make up the bulk of the medical kit for a mission to Mars. A study published in the journal npj Microgravity showed that, out of the 91 medications analyzed, 54 would have expired within 36 months. This included some painkillers. Fourteen medications would have expired before 24 months; these included one advanced life support medication, one anaphylaxis treatment medication, two antibiotics, and one antipsychotic.
They indicated that such expiration dates applied only to drugs in their original packaging; when they often are, as they are on the ISS, repackaged, these dates may be shorter. Previous studies have indicated that astronauts on the ISS report using medications every day, so they are important. But unlike on the ISS, which can be regularly resupplied, such capabilities may not be possible for astronauts on lengthy missions to Mars, and the expiration of medications becomes a large concern.
“Hopefully this work can guide the selection of appropriate medications that last for the duration of a mission or increase the amount of medications brought to account for lowered efficacy,” Buckland said. This research could also provide the knowledge needed for informed consent discussions with exploration crews, allowing them or responsible parties to accept the risk of less effective medications.
That study did not assume that degradation would be more rapid but rather drew attention to the inability to resupply a Mars mission with newer medicines. That inability to resupply is not only an issue for medications but also for other important supplies, such as food. NASA does not normally make information about medications on the ISS public. There are always three to six crew members on board the ISS, which orbits Earth on missions that usually last six months.
Few studies explored the challenge of medication longevity for a mission to Mars, said Thomas E. Diaz, lead author of the study and a pharmacy resident at The Johns Hopkins Hospital. “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 Diaz.
That means the stability and potency of medications in space, relative to Earth, are not well known. That hostile space environment could result in the degradation of drugs, radiation in particular. Under the most optimistic scenario, assuming it has Earth-like stability, most medications will have expired before the end of the Mars 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,” Buckland said. “Astronauts are human. Healthy and well-trained humans, but still humans doing a tough job in an extreme environment.”
It does call for further research and planning if the health and safety of astronauts are to be effectively managed during long-duration missions.