Drugs that are often used in emergencies and typically kept in ambulances may
deteriorate beyond a safe level in a few weeks or months, according to a new
study from Belgium.
That's because - unlike drugs stored in the controlled settings of hospitals
- drugs stored in ambulances are exposed to temperature variations, sunlight and
motion, said Dr Mark Merlin, who studied drug deterioration but wasn't involved
in the new research.
"It's a very different concept and we're learning that expiration dates are
very different (in ambulances)," said Merlin, an emergency physician at Newark
Beth Israel Medical Center in New Jersey.
He added that because few studies have looked at the subject, emergency
physicians and technicians tend to throw out drugs before their printed
expiration date."We don't know when to throw them out and as a result we're
usually very conservative," he said.
For the new study, Sabrina De Winter and her colleagues at the University
Hospitals Leuven compared commonly used injectable drugs stored for one year at
room temperature, in the back of an emergency response vehicle and in a
refrigerator - as they're supposed to be.
The drugs included muscle relaxers cisatracurium and succinylcholine, the
seizure drug lorazepam, methylergonovine to stop women from bleeding after
birth, and the heart, allergy and asthma drug epinephrine.
The researchers checked how much the drugs deteriorated weekly during the
first month of storage, and every other month after that.
As expected, none of the refrigerated drugs degraded to below 90% potency - a
commonly used benchmark for usability.
Methylergonovine and epinephrine also remained stable for more than one year
in the back of an emergency vehicle and at room temperature.
Lorazepam, however, degraded to below 90% within one month in the back of an
emergency vehicle and at room temperature.
Succinylcholine remained safe for about one month in a vehicle and two months
at room temperature.
Cisatracurium remained safe to use in the back of a vehicle for about four
months, but not at room temperature.
Should people be worried?
"These drugs should be removed from EMS backpacks at the end of these time
frames to maintain optimal potency and avoid adverse effects resulting from the
drug degradation," the researchers write in the Annals of Emergency
"The people that have to use them (the drugs) in this fashion are kind of
aware of this," said Dr Howard Mell, a spokesman for the American College of
But Mell, who oversees about 2 000 EMS personnel and others in the suburban
Cleveland area, said it's good that people are studying this topic, because
there had not been a lot of research on drug deterioration in real-world
"I don't think the individual person has to be concerned, but in the same
picture big medical systems need to fund more studies like this because we need
to know how much money we're losing by throwing these drugs away too quickly,"
He added that it's also important to know how long these drugs last because
some are in short supply."I would say we need to be consistent. Just as we're
consistent in the hospital, we need to be consent in ambulances," Merlin