Integration of dose counters in pressurized metered-dose inhalers for patients with asthma and chronic obstructive pulmonary disease: review of evidence

Introduction: An important factor responsible for suboptimal treatment in patients with obstructive airway diseases, which is often overlooked, is running out of medication. Addition of a dose counter to a pressurized metered-dose inhaler (pMDI) allows the patient to reliably track number of actuations, identify when the label claim number of actuations has been reached, and when a new inhaler needs to be purchased. Areas covered: This article discusses the conventional methods for tracking doses in pMDIs, rationale of using dose counters, published evidence of studies, including performance and patient satisfaction with the use of pMDIs with dose counter. A section on the FDA guidance on dose counters and on Cipla's dose counters is also included. Expert opinion: It has been several years since the US FDA guidance on integration of dose-counting mechanisms into pMDIs and some time since pMDIs with dose counters have been available (albeit not with all pMDIs); but their importance has not been fully realized. This can be due to factors such as lack of adequate understanding about dose tracking, limited pMDIs being available with integrated dose counters and absence of a clear consolidation of the need, advantages, guidelines, types and characteristics of dose counters in published articles.