By Andrew M. Seaman
NEW YORK (Reuters Health) - 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 percent 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 percent 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 Medicine.
"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 Emergency Physicians.
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 real-world settings.
"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," Merlin said.
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 said.
SOURCE: http://bit.ly/19P7ScG Annals of Emergency Medicine, online May 28, 2013.