Half of patients admitted to an emergency department for uncontrolled asthma had unknowingly emptied their bronchodilator inhaler, and half of those patients were unfamiliar with identifying remaining doses, in a study conducted at 3 emergency departments (ED) in Boston.

Although most inhaler products incorporate a dose-counting meter, in response to a 2003 recommendation of the US Food and Drug Administration (FDA), only one-third of the patients admitted to an ED for uncontrolled asthma had been advised to keep track of available doses.

Led by Kohei Hasegawa, MD, MPH, attending physician, Massachusetts General Hospital and Associate Professor of Emergency Medicine, Harvard Medical School, researchers noted that overestimating the remaining doses of short-acting beta-agonist (SABA) can cause patients to use their inhalers past the labeled actuations. They noted that the drug delivered per actuation can range anywhere from 20% to 80% of the needed therapeutic dose.