Efficacy and safety of inhalation therapy in chronic obstructive pulmonary disease and asthma

The inhaled route has a number of well-recognized advantages over other routes for administration of drugs to the lungs. As the drug is delivered directly to its required site of action, only a small quantity is required for an adequate therapeutic response. Consequently, there is a low incidence of systemic side-effects compared with oral or intravenous administration. In addition, the onset of action of inhaled drugs is generally faster than that achieved by oral administration. Factors that can affect the quantity of inhaled particles reaching the lungs and their topographical distribution are manner of inhalation, aerosol characteristics and subject characteristics. The main types of inhaler device are metered-dose inhalers (MDIs), dry powder inhalers (DPIs) and nebulizers (jet and ultrasonic). There are advantages and disadvantages associated with all types of currently available inhaler device and there is still a clear need to develop more efficient devices that are easy to use. Respimat (Boehringer Ingelheim) is a novel soft mist inhaler that operates via a mechanism utilizing mechanical power rather than gas propellants, and represents an exciting development in this field.