The relationship between prescribed and delivered doses of inhaled corticosteroids in adult asthmatics

A model was developed to estimate the impact of adherence and inhalation te chnique over time on delivered doses of inhaled corticosteroids (ICS) for a sthmatics using metered-dose inhalers (MDIs) and dry powder inhalers (DPIs) . Factors affecting inhalation technique include ongoing training, inhalati on device, spacer use (with MDIs), and natural ability. Model parameters we re derived from a literature review or were estimated from clinical experie nce. Analyses demonstrated that most patients receive a fraction of prescri bed ICS doses over time. The model may be used to better understand the imp act of increasing ICS dosages and to estimate the likelihood of patients be ing underdosed.