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.