Inhaler devices for asthma.

Inhalation therapy is now the mainstay of treatment for asthma but for many patients such treatment is still not optimal. The delivered dose can vary widely between different delivery systems, and between patients, depending on how well they use a particular device. Many new inhaler devices are now available, and their competing promotional claims can confuse both prescribers and patients. In this article we review the devices marketed and discuss how to select the best one for a particular patient.