Peggy Peck

October 27, 2004

Oct. 27, 2004 (Seattle) — Heating formoterol capsules to 70°C — the inside temperature of a metal mail box in Phoenix, Arizona — significantly degrades the capsule and results in less formoterol delivered by inhalation, according to research presented at CHEST 2004, the 70th annual meeting of the American College of Chest Physicians.

Gregory T. Chu, MD, a pulmonary and critical care medicine research fellow at the Carl Hayden Veterans Affairs Medical Center in Phoenix, Arizona, told Medscape that the finding suggests that "clinicians should discuss the use of mail order pharmacies with patients and should alert patients to the potential risks of leaving mail ordered drugs in mail boxes or other areas where heat exposure is likely." He noted that a similar effect was likely with formoterol left inside cars during hot summer months or in the areas such as the southwest or southern U.S.

Dr. Chu said that he and his colleagues were alerted to the problem when patients showed them "discolored and disfigured gel caps containing formoterol." Dr. Chu showed the deformed gel caps to a pharmacologist who accurately diagnosed the problem. "She took one look at them and said, 'It looks like they were burned.' " That led Chu to his mailbox — when he put a thermometer in the mailbox, "It registered 70°C."

In the study, he and his colleagues heated formoterol capsules in original blister packaging to 70°C (158°F) for four hours. Capsules were removed from packaging and a vacuum setup was then used to dispense the formoterol into a filter tube using the inhalation technique and device provided by the manufacturer. Weights of the filter tube pre- and postdispensation were obtained to calculate simulated drug delivery. These measurements were compared with those obtained from capsules that had not been exposed to heating.

The change in filter weights from capsules that underwent heating was significantly less than that obtained from capsules that had not been heated (5.5 ± 2.7 mg vs 12.7 ± 1.5 mg; P < .05). In addition, visual inspection of heated capsules revealed gross distortion of capsule as well as visible clumping of formoterol.

Philip Marcus, MD, PhD, an associate professor of clinical pharmacology at the State University of New York Stonybrook and associate dean of curriculum development at New York College of Osteopathic Medicine, told Medscape that he was not surprised by Chu's findings. He noted that 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 said.

In the case of formoterol, the problem of heat exposure 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," Dr. Marcus said.

Physicians should counsel patients to read the storage instructions on medicines, Dr. Marcus pointed out. If there are cautions about heat exposure, patients should make sure the mail order pharmacy ships the drugs in a way that avoids this problem.

CHEST 2004: Poster 805S. Presented Oct. 27, 2004.

Reviewed by Gary D. Vogin, MD


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