Millions of Americans receive their prescription drugs from mail order pharmacies (search), but new research suggests that mail order drugs may lose some of their potency.

Among the drugs most at risk for mail order damage are asthma medications, says Gregory T. Chu, MD, a pulmonary and critical care medicine research fellow at the Carl Hayden Veterans Affairs Medical Center in Phoenix.

Chu tells WebMD that many older asthma patients are disabled, which means they rely on the convenience of mail order drugs. However, mail delivery means that prescription drugs are exposed to environmental factors such as extreme heat or cold that can affect potency. Chu says he and his colleagues were alerted to the problem when patients showed them "discolored and disfigured gel caps containing [Foradil]."

Foradil (search), a prescription drug used to treat asthma, is a powdered substance that comes in a capsule that is placed in a special inhaler. The contents of the capsule are inhaled into the lungs. Chu showed the deformed gel caps to a pharmacologist who provided the clue to what had happened.

"She took one look at them and said, 'It looks like they were burned.'"

That clue led Chu to his mailbox. When he put a thermometer in the mailbox, it registered 158 degrees Fahrenheit, says Chu, who reported his findings at the annual meeting of the American College of Chest Physicians. He says the heat not only melts the gel cap but also "appears to make the powder clump."

The bottom line, he says, is that the patient would be inhaling less than the recommended dose of the drug. Philip Marcus, MD, PhD, associate professor of clinical pharmacology at the State University of New York in Stonybrook and associate dean of curriculum development at the New York College of Osteopathic Medicine, tells WebMD that he is not surprised by Chu's findings.

He says most medicines "are not meant to be stored at extreme temperatures." Moreover, several drugs "will deteriorate when exposed to extreme heat or extreme cold."

He says the problem of heat exposure and Foradil is "not unknown."

"By and large, mail order pharmacies do a good job. I have many patients who receive this drug by mail, and the mail order pharmacies pack the drug in dry ice to avoid this problem," Marcus says.

He says patients should read the storage instructions on medicines. If there are cautions about heat exposure, he says patients should make sure the mail order drugs are shipped in a way that avoids this problem.  Chu says patients should avoid mail order drugs that look suspicious when "they unwrap the package."

By  Peggy Peck, reviewed by  Brunilda Nazario, MD

SOURCE: CHEST 2004, the Annual Meeting of the American College of Chest Physicians, Seattle, Oct. 23-28, 2004. Gregory T. Chu, MD, pulmonary and critical care medicine research fellow, Carl Hayden Veterans Affairs Medical Center, Phoenix. Philip Marcus, MD, PhD, associate professor of clinical pharmacology, State University of New York in Stonybrook; associate dean of curriculum development, New York College of Osteopathic Medicine.