Mail-order drugs that are exposed to too much heat—in a car, transport truck or mailbox—may become less effective, say researchers.


To test the effects of heat on medications delivered by mail, lead investigator, Dr. Gregory T. Chu, former senior pulmonary and critical care fellow atCarlT. Hayden Veterans Affairs Medical Center in Phoenix, and his colleagues recreated the conditions of a scorching Arizona mailbox in their lab. In the heat of an Arizona summer, a mailbox can reach a parching 158° Fahrenheit.

"The genesis of this study was our patients were actually calling us and telling us that that drug was being delivered to them in unsuitable conditions," says Chu.

In the study, capsules of the asthma drug formoterol (Foradil), still in their original blister packaging, were heated to 70° Celsius (or 158°F) for four hours.

When they were inspected, the heated capsules appeared grossly distorted and the formoterol formed clumps, according to Chu. His team also tested the effectiveness of the heat-exposed medication and found it delivered less than half of its intended dose.


With more Americans receiving prescriptions by mail, some medication-safety experts worry that exposing certain medications to extreme heat or cold could render them ineffective.

Their concern is not just limited to prescriptions that are received by mail or to formoterol, the focus of Chu's study.

"This is far more broad than what they present it to be," explains Matthew Grissinger, director of error reporting programs at the Institute for Safe Medication Practices, a Pennsylvania-based drug safety organization.

Every prescription comes with information indicating the safe temperature for storing that medication, he notes. While some medications must be refrigerated, others should be kept at room temperature. 'Any time you exceed that temperature, there's no guarantee what you're going to get," Grissinger says.

Think about the heat and humidity in the bathroom—one of the worst places to keep prescription medications.


However, Ann Smith, a spokeswoman for Medco Health Solutions, which dispenses approximately 78 million mail-order prescriptions a year, says the study fails to mention safe packaging requirements.

A mail-order pharmacy such as Medco has procedures in place for temperature-sensitive medications, including formoterol, she says. Such medications are shipped overnight in insulated packaging that includes ice or cold gel packs, depending on the type of medication and seasonal weather conditions.

For more tips on safe medication use, visit the Web site of the National Council on Patient Information and Education at

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