Prescription of inhalers in asthma and COPD: towards a rational, rapid and effective approach.

Inhaled medication is the cornerstone of the pharmacological treatment of patients with asthma and COPD. The major two classes of inhaled medication include corticosteroids (ICS) and bronchodilators. There is a wide diversity in molecules in both classes. Moreover, there is a wide variation in delivery systems. The correct use of inhalers is not granted and patients often incur in many mistakes when using pMDIs and DPIs, despite repeated instructions. A better matching between patient and device could be accomplished if the physician is aware of: (1) the patient characteristics (disease, severity, fluctuation in airflow obstruction, etc); (2) what class of medication is indicated; (3) where in the lung the medication should be delivered; and, (4) how this can be best achieved by a given device in this specific patient. We focus on the prescription of pMDIs and DPIs at the GP office or at the outpatient clinic of the hospital, and we propose an evidence based approach enabling the caregiver to make a rational choice in only a few minutes by just considering the following four simple questions: Who?, What? Where? and How? (the so-called 3W-H approach).