Expiring medications could pose problem for Mars astronauts

When it comes to crewed missions to Mars there is no shortage of hazards, from space radiation to a hostile environment. Now researchers have found another snag: many of the medicines astronauts may take with them are likely to expire before they return to Earth.

Researchers say they have discovered a host of medications used in space have a shelf life of three years or less – a problem given Nasa expects a mission to Mars to take roughly 36 months.

Dr Dan Buckland, the senior study author from Duke University School of Medicine, said that on Earth, expired medication was usually less effective, although by how much is unpredictable.

“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 (FoI) request to gather a list of the medications onboard the International Space Station (ISS). While the exact medications that would be taken to Mars are not yet known, Buckland said those on the ISS were likely to make up the bulk of a medical kit for such a mission.

Writing in the journal npj Microgravity, the team revealed how they found terrestrial shelf-life data for 91 of the 106 medications on the 2023 ISS list, with their maximum shelf life dates suggesting 54 of the medications would expire by 36 months, including certain painkillers.

Fourteen of the medications would expire by 24 months, including one advanced life support medication, one anaphylaxis treatment medication, two antibiotics and one antipsychotic.

When each medication’s minimum shelf life was considered, 89 of the 106 medications were found to expire by 36 months.

The authors said the expiry dates referred to the drug in its original packaging, meaning they may be shorter if repackaged, as they often are on the ISS.

Previous studies have shown astronauts on the ISS report daily use of medications onboard, indicating their importance.

But while the ISS can be regularly resupplied, such capabilities – as well as emergency evacuation – may not be possible for astronauts undertaking lengthy missions, making the expiration of medications a concern.

“Hopefully this work can guide selection of appropriate medications that last for the duration of a mission or increasing the amount of medications brought to account for lowered efficacy,” Buckland said.

“Alternatively, this could provide the knowledge needed for informed consent discussions with exploration crews that allow them or responsible parties to accept the risk of less-effective medications.”