ABSTRACT
Considering the large surface area of the lung and the absence of fi rst-pass metabolism, the alveolar and bronchial epithelium is a unique site for drug absorption. Inhalation therapy is now widely recognized as the best way of administering drugs for deposit into the lungs of patients with asthma. In the last 50 years, there has been a focus on developing appropriate formulations and inhalation devices to optimize the delivery of asthma medications, particularly corticosteroids and β2 agonists, into the airways. Currently, more than 100 different inhaler/drug combinations are available for the treatment of asthma. The prevalence of these inhalers has resulted in a wide range of choices for the healthcare provider and in confusion for both clinicians and patients regarding how to use these devices correctly. The efficacy of these drugs depends on their proper inhalation into the lungs. A poor inhaler technique can markedly reduce the proportion of drug that reaches the lung. Several studies have shown that incorrect inhalation technique is associated with poor asthma outcomes, not only in terms of suboptimal asthma control, but also an increased risk of emergency department visits and of death due to asthma exacerbations (Giraud and Roche 2002, Hesselink et al. 2001). Poor inhaler technique thus has a substantial impact on both the individual and on society as a whole. The present chapter focuses the inhaler devices, with particular emphasis on inhalation technique, and addresses several approaches for improving and maintaining adherence to proper inhaler use.
