Mail-order prescriptions exposed to excessive heat may become significantly less effective for patients

Oct 28 2004

Mail-order prescriptions exposed to excessive environmental heat, such as temperatures found in mailboxes and car interiors, may become significantly less effective for patients.

In a new study presented at CHEST 2004, the 70th annual international scientific assembly of the American College of Chest Physicians (ACCP), formoterol, a common inhaled asthma medication, delivered less than half of its expected dosage and showed significant physical changes after being exposed to 150ºF for 4 hours.

"Inhaled medications are calculated to deliver a specific dosage for each use. Extreme temperatures can affect medications in just a few hours, causing them to deliver inaccurate dosages, making the medications less effective," said the study's lead author Gregory T. Chu, MD, FCCP, Carl T. Hayden Veterans Affairs Medical Center and Banner Good Samaritan Medical Center, Phoenix, AZ. "For patients with respiratory conditions, who rely on their medications to relieve acute breathing difficulties, inaccurate medication dosage can lead to serious medical consequences."

Researchers from Carl T. Hayden Veterans Affairs Medical Center tested the effects of heat on powder-filled formoterol capsules and its effects on drug delivery. Formoterol capsules were heated in their original packaging for 4 hours at 150ºF, similar to the temperature found in the inside of an Arizona mailbox. Capsules were removed from their packaging and dispensed 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. Results showed that filter weights of heated medications were less than half of those unexposed to heat, showing that a significantly less amount of the drug had been dispensed after it had been heated. In addition, capsules exposed to heat were grossly distorted in appearance and showed visible clumping.

"Mail-order prescriptions have become increasingly popular among patients in the last few years. However, many patients do not realize that most medications have storage requirements regarding exposure to excessive temperatures," said study coauthor Richard A. Robbins, MD, FCCP, Carl T. Hayden Veterans Affairs Medical Center. "We strongly advise that patients avoid exposing medications to the extreme heat found in mailboxes and car interiors and inspect all mail-order medications prior to consumption." According to researchers, asthma medications and other prescriptions delivered in the extreme-heat states of the Southwest are not the only medications at risk. Any situation that exposes a drug, particularly those with gelatin capsules or containing powder, to excessive temperatures may put a patient at risk for consuming altered medication.

In 2003, mail order represented an estimated 17 percent of retail prescription drug sales in the United States, totaling more than $35 billion in sales and an increase of more than 15 percent from sales in 2002.

"With the increasing popularity of ordering medications by mail, retailers who fill prescriptions by mail must place additional focus on the proper packaging and shipping requirements for at-risk medications," said Paul A. Kvale, MD, FCCP, President of the American College of Chest Physicians. "It also is important for patients to review manufacturer storage directions to ensure that medications are not exposed to extreme temperatures, either inside or outside the home."

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