Loss of bronchodilator medication in priming a conventional metered dose inhaler: a cost of treating asthma.

The direct and indirect costs of lost medication resulting from the required "test dose" to reestablish the prime of active drug in the conventional metered-dose inhaler (MDI) valve and the uncertainties associated with "tail-off" increase the cost of using a conventional chlorofluorocarbon driven MDI to deliver aerosolized bronchodilator in the management of asthma. In this article, the author establishes a basis for estimating the cost of wasted medication.