Modifying delivery technique of fenoterol from a metered dose inhaler

Twenty-eight outpatients with bronchial asthma inhaled one puff of fenoterol hydrobromide (200 mcg) from a metered dose inhaler, either held in three different mouth positions or from three different starting lung volumes. Inhaling bronchodilator with closed mouth was significantly less effective than when the mouth was open, or when the inhaler was four cm from the open mouth. Inspiration of drug beginning from 75% of vital capacity resulted in better bronchodilation than starting at residual volume. Patients are likely to obtain maximum benefit from metered dose inhalers when the mouth is open and the inspiratory volume is small.