Importance of inhaler devices in the management of airway disease

The delivery of drugs by inhalation is an integral component of asthma and chronic obstructive pulmonary disease (COPD) management. However, even with effective inhaled pharmacological therapies, asthma, particularly, remains poorly controlled around the world. The reasons for this are manifold, but limitations of treatment guidelines in terms of content, implementation and relevance to everyday clinical life, including insufficient patient education, access to health care and cost of medication as well as poor inhaler technique are likely to contribute. Considering that inhalation therapy is a cornerstone in asthma and COPD management, little advice is provided in the guidelines regarding inhaler selection. The pressurised metered dose inhaler (pMDI) is still the most frequently prescribed device worldwide, but even after repeated tuition many patients fail to use it correctly. In addition, the correct technique can be lost over time. Although several improvements in pMDIs such as a change in the propellant and actuation have resulted in improvements in lung deposition, many dry powder inhalers (DPIs) are easier to use. However, these devices also have limitations such as dependency of drug particle size on flow rate and loss of the metered dose if the patient exhales through the device before inhaling. Improvements in using inhalation devices more efficiently, in inhaler design for supporting patient compliance, and advances in inhaler technology to assure drug delivery to the lungs, have the potential to improve asthma and COPD management and control. New and advanced devices are considered being helpful to minimise the most important problems patients have with current DPIs.