ABSTRACT
The major advantage of topical administration of a drug is the possibility to achieve high local concentrations and to avoid high systemic concentrations. In clinical practice, the decision of a physician to initiate a treatment with inhaled β2-agonists or glucocorticosteroids in patients with asthma or chronic obstructive pulmonary disease (COPD) is easy, as their efficacy is beyond any discussion. Adverse reactions to aerosolized drugs are rare (1) and may be circumvented by choosing an alternative formulation or an alternative drug. To deposit in the airways, the drug must be aerosolized, for which an inhalation system is necessary. Pressurized metered dose inhalers (pMDIs), dry-powder inhalers (DPIs), and nebulizers are the currently used delivery systems. Health care providers involved in aerosol therapy should be critically informed about these systems in order to make appropriate comparisons and intelligent choices for their patients. Indeed, each formulation is a unique combination of a drug and a device, and it is that combination, rather than the drug itself, that causes a portion of the emitted dose drug to be deposited in the airways to elicit the clinical effect.
