Not all asthma inhalers are the same: factors to consider when prescribing an inhaler

Abstract

National and international asthma guidelines stress that before making changes to patients' therapy their compliance and inhaler technique should be checked. This review addresses these issues and highlights the differences between inhalers in terms of inhaler technique, individual ability/competence, and ease of use. The advantages and disadvantages of metered-dose inhalers (MDIs) and dry powder inhalers (DPIs) are presented. The reformulation of beclometasone MDIs is discussed since there has been some confusion over prescribing and Regulatory Authorities have recommended that these should be prescribed by brand name and not generically. This review should provide prescribers with an update to help them appreciate the differences between inhalers thereby optimising each patient's inhaled treatment.

Inhaler technique and training in people with chronic obstructive pulmonary disease and asthma

“…There is a complex interaction between these three factors that results in the need for different techniques for different inhalers [37,38]. Patients using a pMDI should use a slower inhalation [37,39], compared with a DPI, which requires a faster inhalation rate [37,40].…”

“…This means that the patient needs to apply less effort to inhalation to generate the appropriate inspiratory flow and optimum drug deposition. A low-resistance device, such as an MDI, means that it is relatively easy to generate too great an inspiratory flow, essentially inhaling too fast, which is a common error in the use of MDIs [37,38,52].…”

Characterisation of dry powder inhaler formulations using atomic force microscopy

“…At the same time, they need to be low enough to ensure dispersion and disaggregation during inhalation (Cui et al, 2014), as only small particles and agglomerates (<5 mm) can penetrate the deep lung and be therapeutically active (Cui et al, 2014;Zeng et al, 2000). The drug load itself also affects formulation performance along with the choice of inhaler device (De Boer et al, 2005) and the patient's individual breathing pattern (Chrystyn and Price, 2009;Heyder, 2004). The relationship between particulate characteristics and their respective effects on formulation performance have been studied and reviewed widely over the years (Adi et al, 2013;Chan, 2008;Chow et al, 2007;Donovan and Smyth, 2010;Guenette et al, 2009;Healy et al, 2014;Zellnitz et al, 2014;Zeng et al, 2000;Zhang et al, 2011).…”

Assessing and accessing the small airways; implications for asthma management

“…The use of an HFA propellant is necessary, but it is not the only prerequisite for extrafine particle formulations. Indeed, most HFA pressured metered dose inhalers (pMDIs) on the market have similar characteristics to the corresponding CFC pMDIs [67]. To date, there are some single-agent extrafine formulations on the market (beclometasone, ciclesonide, formoterol), and only one combination product available (beclometasone/formoterol) [68].…”